Paul's object in Hebrews 6 is to encourage every believer to steadfastly persevere in the faith, lest we be numbered among those who, having professed faith in Christ, "fall away" into utter apostasy and eternal ruin. What is it to fall away? To lie is not to fall away. Abraham did that. To fall away is not to commit adultery or murder. David committed those crimes. Falling away is not quitting the ministry. Both Peter and John Mark once did that. Not even a temporary denial of Christ in time of fear is to fall away. Peter did that. To fall away is to willingly depart from the faith, worship, and obedience to Christ, to break away from the rule of Christ and cast off the yoke of submission to him, because of the offense of the gospel, the love of the world, personal relationships, or personal ambitions (John 6:66; Heb. 10:25-26; II Tim. 4:10; III John 9). While the Word of God assures us that no true believer can or will ever fall away, it is obvious to all that many who profess to be believers do fall away. Those who do are reprobate, willingly despising the blood of Christ (Heb. 10:29; II Pet. 2:20-22). "They went out from us, but they were not of us" (I John 2:19).