To understand and profit from this lesson, it is essential that you read carefully Hebrews 10:23-32.
Having begun the Christian life, there is nothing more vital or important to the continuation of that spiritual existence, than that we be faithful to God. The inspired writer of Hebrews first exhorts us to “hold fast the profession of our faith without wavering” (10:23). To help us know what he is saying to us and apply it to our lives in these modern times, let us read this language of the New Testament in speech such as we use: “Let us, without ever wavering, keep on holding to the hope that we profess” (Williams). The New English Bible renders this verse: “Let us be firm and unswerving in the confession of our hope.”

The phrase “let us hold fast” literally means “to hold in a firm grasp, to have in full and secure possession, the confession and the promises which we have openly and solemnly avowed to God.” In the process of our becoming Christians, we confessed that we believed in our hearts that Jesus Christ is the Son of the Living God. We were baptized into him and arose to walk in newness of life (Rom. 6:34). The apostle admonishes us to be steady, firm, unmoved and unwavering in our faithfulness to this great acknowledgment and all that it implies. The tragedy in the church today in this country (as well as in other countries) is that many have begun the Christian life filled with enthusiasm, love and resolution; but they have not “held fast.” Their interest has waned from those first days; their goal has become clouded and obscure; their values undergo change and assume a twisted and distorted shape and their vision reverts to the attractions of this world. Though there is no way to estimate accurately how many Christians there are who are not really faithful in their private and public duty to the Lord, it is likely a conservative guess that fully one half of those who have been “baptized in Christ” are not now “holding fast.”
Paul discussed this same problem and used a similar admonition to the Colossians: “If ye continue in the faith grounded and settled, and be not moved away from the hope of the gospel...(1:23). This says to us that a Christian must remain true and steadfast, firm and immovable in the faith. He must have “staying power”; he must persevere, never abandoning his duty and never allowing himself to be shifted away from the gospel.
Luke continues to show how tremendously important it is for the Christian to be faithful in his service to God by relating the example of those very first disciples who were baptized on Pentecost: “And they continued steadfastly in the apostles’ teaching and fellowship, and in the breaking of the bread, and in prayers” (Acts 2:42). It can help one immeasurably, individually, as a child of God, and the cause of Christ, generally, if he will take h​​​​​​​eed to this divinely approved example which God intended to serve as a standard after which to pattern our own conduct. “And they continued steadfastly...” The sense and significance of this is: “To persist in adherence to a thing; to be intently engaged in; to attend constantly; unremitting continuance to a thing; to be devoted to” (Thayer). In this we have the secret, the answer, to our strength and growth. The Twentieth Century New Testament translates this verse, “They were regularly present”; Weymouth renders it, “And they were constant in attendance”; and the New English Bible presents, “They met constantly”. Churches in this country are weak because there is not this sense of loyalty and constancy among the members. Congregations are small because they have lacked devotion and steadfastness in worship and service to God.

There are two very obvious reasons that come to view, when Christians read the New Testament, why they should be faithful to God. 
First, it is necessary, or requisite, to our salvation. I should like to make this clear that it will be perfectly understood by all who read this with an open heart. Our faithfulness to God in worship, with other Christians to honor Christ, constitutes the absolute essence, the fundamental nature of our religion.

If we are not faithful, our religion is make-believe and hollow mockery.  Much preaching is done by us about faithfulness, but where is the practice? Jesus said: “Bs thou faithful unto death, and I will give thee a crown of life” (Rev. 2:10). When he drew a picture of the judgment in Matthew twenty-five (2f), the blessings of eternal life were dispensed to the faithful — to those who were reliable, dependable, and trustworthy. They had proved through life that they were sound and faithful servants of Christ. “Well done, thou goad and faithful servant: thou hast been faithful over a few things, I will make thee ruler over many things: enter thou into the joy of thy Lord” (Matt. 25:21). In the second place, Christians ought to be faithful because God has been faithful to them. Our text says, “for he is faithful that promised” (verse 23). We can be sure that he will not fail us, as so many of us have failed him. There is no question but that he will do what he says. ‘‘God is faithful by whom ye were called into the fellowship of his Son, Jesus Christ our Lord” (1 Cor. 1:9). God is utterly dependable and entirely trustworthy. Are we? “Faithful is he that calleth you, who also will do it” (1 Thess. 5:24). He will not fail you, but he will keep his promise, fulfill his vow, and complete his work. Out of gratitude for what he has done for us, and his faithfulness to us, we should be faithful to him.
The Authorized, or King James Translation, of verse 25 reads: “Not forsaking the assembling of ourselves together...” This is quite clear enough for all to see. There is no blur nor dimness in this language, but the original speech of the New Testament, and more modern translations, make the truth of this passage more easily understood, more sharply defined and more unmistakably distinct. Knox: “Not abandoning our common assembly”; Berkeley: “Not neglecting our own church meeting”; New English Bible: “Not staying away from our meetings”; Phillips: “And let us not hold aloof from our church meetings.” The language of the inspired writer of Hebrews is even more positive. Mr. Thayer says this is “a gathering together in one place, the religious assembly of Christians; and that we are not to “abandon or desert” it. With this many other scholars agree, such as Arndt & Gringrich, Abbott-Smith, and W. E. Vine. Arndt & Gringrich and Vine add the thought: “do not leave behind.”

James Moffatt, reputable scholar, translator, and historian, says that there were a number of reasons why, in that day, many Christians were absent from the assemblies of the saints.
1. Some were deterred in their attendance by fear of persecution. There are yet some places in the world where it is dangerous for Christians to meet together to worship God. Some of God’s people were so strong in that day that they met in caves and dens of the earth to observe the suffering and death of Christ by eating the Lord’s Supper. Even when they were discovered by opposing heathen authorities, they would still partake of the bread and wine in the knowledge that the soldier’s bow was drawn to send an arrow through their heart. O, that we had Christians with this conviction in our time.
2.    Moffatt says some were absent because they felt no interest in it. Christ died for them, rescued them from the bondage of sin, gave them the Lord’s Supper, and commanded them to observe it each week to keep alive in their hearts the memory of his suffering and death on their behalf, but they felt no interest in it. This describes the attitude and temper of so many members of the church in the 20th Century. They forsake the assembling of themselves together because they couldn’t care less. I frequently make inquiry about the absence of a well-known member of the congregation only to be told that he (or she) stayed at home, or was having company, or had gone visiting. To miss the memorial of the death of Christ does not seem to give them any concern at all — not even the slightest twinge of conscience.

3.    The historian said that many had doubts about the necessity of these regular Christian assemblies. Two thousand years have passed, and people are still arguing about the necessity of faithfulness, trying to excuse their disinterest and misconduct, but it is very poor defense in the face of the divine mandate of God. “Do not forsake your coming together...”

4.    Another reason why some Christians defected from God’s service and absented themselves from worship was that they were engaged in business. Times have not really changed. Some are too busy today to meet regularly with the brethren to worship and praise God and to remember the sacrifice of his Son. Frequently, I drive many miles to meet with my brethren in various congregations over the country. This is a great pleasure to meet and to worship with others of “like precious faith.” Often some of those brothers and sisters I have met on former occasions are absent from the Lord’s service. Questions of concern are asked about them. It is possible that illness could have kept them from worship, and sometimes this is the case, but disappointment and depression fill my heart when I learn that some “good sister” did not come to worship this Lord’s Day morning because she is preparing Sunday dinner, and some “good brother” is engaged in the pursuit of his business. Is this faithfulness? Is this true Christianity? With such people, Christianity is a side line; they are simply playing at the highest and noblest calling in the world, somewhat like children “play church.” They remind me of the people on the occasion when Jesus came to the ruler’s house to raise his daughter from the dead.. He said, “The maid is not dead, but sleepeth, and they laughed him to scorn” (Matt. 9:24). I believe that a Christian who forsakes the assembly to prepare food for family or friends or to attend to his personal business is “laughing Jesus to scorn”! I think it is the equivalent of chuckling (smiling) at his death, ridiculing his sacrifice and showing disrespect for the very purpose of his coming into the world.

Is one guilty if he deliberately stays away from the house of God, and does not, with other Christians, commemorate the suffering and death of Christ by eating the Lord’s Supper? The Hebrew writer names three grievous, deplorable sins of which a Christian becomes guilty when he forsakes the assembly.
1.    He has trampled underfoot the Son of God (Heb. 10:29).     In ancient times when an enemy was defeated, the victor would literally trample him underfoot. He would step roughly and tread triumphantly upon him. To the multitudes, this was a kind of game, and they shouted their approval and took pleasure in the success of their army over the adversary. Jesus used this word “trample” in Matthew 7:6. “Neither cast your pearls before swine, lest they trample under their feet, and then turn and attack you.” When one intentionally and purposely forsakes the assembly of the saints (whether to prepare food, visit friends, or attend to business), he has done to Christ what the hogs do to precious pearls when they trample them in the muck and mire and filth of the hog pen. Do you believe you can do this to Christ and escape the displeasure and punishment of God?

2. He is guilty of counting the blood of Christ as common (Heb. 10:29).
This term denotes “violation.” He has violated the blood of the covenant.” He has abused and treated with irreverence the blood Jesus shed on the cross. You see, the Christian is supposed to drink the memorial of his blood upon the first day of every week (Acts 20:7; 1 Cor. 10:16; 11:25, 26). If he neglects to do this, he has debased and vulgarized and made common, cheap and ordinary the blood of Jesus Christ shed for his sins. I am afraid that too many Christians have not considered the seriousness of their sin of carelessness and indifference. It is fraught with fearful and eternal consequences.

3.    Me has despised the spirit of divine grace.
would feel insulted if you inferred they were not Christians, who are described in the words of these scholars. If those Christians (?) who are neglectful of their duties, who are irregular in worship to God, and who are not in their place, were withdrawn from, as Paul commands, many people in this country would be affected. Such correction needs to take place without delay. If the church would exercise discipline upon those who “walk disorderly,” as the Lord directs it to do, there would be greater spirituality among its members, more respect for it in the eyes of the world, a. deeper devotion and purity within its ranks, and a more widespread influence that would guarantee its strength and growth.

James A. Garfield was President of the United States of America, taking office March 4, 1881. On his first Sunday in Washington after his inauguration, a member of the cabinet insisted that a meeting must be called to discuss a matter that threatened a national crisis. The President refused on the grounds of another appointment. The cabinet member then insisted that the national matter was of grave importance, and that Mr. Garfield should break his engagement, but Mr. Garfield refused to do so.Then the cabinet member remarked: “I would be interested to know with whom you have an engagement so important it cannot be broken.” President Garfield replied: “I will be as frank as you are. My engagement is with the Lord, to meet Him at His house at His table at 10:00 tomorrow morning, and I shall be there.”

May God help us to be so dedicated to Him!