After baptism, it is essential to continue in obedience of all the things we have been commanded by Christ to do. Of course, we all fail daily in matters of walk and conduct. We confess our failures, pray for forgiveness and strength to overcome our weaknesses, and go on.

When it comes to obeying the truth, it is a command by Christ that we walk with those who are walking in the truth, and that we refuse to walk with those who are walking in error. If one defends his sin, or if he strays from the truth of the Gospel, we cannot escape our own responsibility apart from separating from those in error.

John, the apostle of love taught:

2JO 1:9-11 Whosoever transgresseth, and abideth not in the doctrine of Christ, hath not God. He that abideth in the doctrine of Christ, he hath both the Father and the Son. If there come any unto you, and bring not this doctrine, receive him not into your house, neither bid him God speed: For he that biddeth him God speed is partaker of his evil deeds.

The word "partaker" means fellowship which also means partnership. If we fellowship those whose beliefs or actions are in error, we ourselves become guilty for fellowshiping such, and become partners in the error.

The Apostle Paul explains why, by giving us an example. The ecclesia at Corinth had among them a fornicator. They didn't want to do anything about it. Paul told them they had to, and he also told them why.

1CO 5:4-7 In the name of our Lord Jesus Christ, when ye are gathered together, and my spirit, with the power of our Lord Jesus Christ, To deliver such an one unto Satan for the destruction of the flesh, that the spirit may be saved in the day of the Lord Jesus. Your glorying is not good. Know ye not that a little leaven leaveneth the whole lump? Purge out therefore the old leaven, that ye may be a new lump, as ye are unleavened. For even Christ our passover is sacrificed for us:

The commandment was to deliver him back to Satan, that is, back to the world, and out of the ecclesia till he understood the truth as it is in Jesus. Because "a little leaven leaveneth the whole lump." That is, the error, if uncontrolled will spread in the body until the whole truth is lost.