The Scriptural teaching that we are saved by faith and not by works have led men to feel that baptism, a work, is not essential for salvation. This is a false idea on two fronts. First, the "works" described as unable to bring life are not works in general, but the works commanded in the law of Moses. Paul wrote:

GAL 2:16 Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified.

So we cannot be justified by the works of the Mosaic law. But does that mean baptism is not essential? No, the second point is equally clear. Christ gave the command to be baptized, and we may not ignore the commandments of Christ and be blameless. The Apostle John recorded this of Jesus:

JOH 3:5 Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God.

Jesus explains here that baptism is not an option. A man cannot enter the kingdom of God unless he is born of water, in his baptism, and of the spirit, after his resurrection to life. Nothing could be plainer.

And to emphasize this point, Peter further explains about baptism:

1PE 3:20-21 Which sometime were disobedient, when once the longsuffering of God waited in the days of Noah, while the ark was a preparing, wherein few, that is, eight souls were saved by water. The like figure whereunto even baptism doth also now save us (not the putting away of the filth of the flesh, but the answer of a good conscience toward God,) by the resurrection of Jesus Christ:

How many souls were saved who did not get onto the ark? None! And this, Peter says, is our figure or symbol concerning salvation through water. As none were saved who did not get on the ark, neither will any be saved who do not become baptized after learning, believing, and committing themselves to obeying the truth.

Therefore Christadelphians teach:

XVI.--That the way to obtain this salvation is to believe the Gospel they preached, and to take on the Name and service of Christ, by being thereupon immersed in water, and continuing patiently in the observance of all things he has commanded; none being recognized as his friends except those who do what he has commanded.