Works-based heretics and members of idolatrous pagan cults such as Catholicism and Orthodoxy like to quote Acts 2:38 to try and prove that baptism is necessary for salvation (in spite of many dozens of verses teaching that salvation is by faith alone).
Acts 2:38 Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost.
Funny how they always miss Acts 2:21 in the same section which says, "And it shall come to pass, that whosoever shall call on the name of the Lord shall be saved."
So what does Acts 2:38 mean?
The following article was originally written by S. H. Ford, though I've made some slight edits.
A short, plain, exposition of the words of Peter, as quoted above, having been requested, there follows an unelaborated exegesis of the passage. To bring the meaning clearly out, let it be asked WHAT IS BAPTISM FOR?
A scriptural investigation and answer to that question shed light and beauty over all that is connected with the ordinance. We answer, baptism is for a testimony or witness. It is a memorial rite. It is a commemorative act. It is a monumental institution. It is a voiceful witness of certain wondrous facts and living principles. It is a witness which speaks the same in all languages, and to all tribes, and in all ages.
Of the Lord's Supper the same may be said. This is also for a testimony, a witness, speaking to all ages the same grand and melting story. What is the Lord's Supper for except it be for a testimony of his death and our trust in that death? “Ye do shew forth my death till I come.” It is for that or in view of that. It connects His first coming with His second coming.
Baptism is for his resurrection, and our hope based upon it. It is for that or in view of that. We need not pause to prove this. It is self-evident. Now as we have “redemption through his blood,” so are we saved “by his resurrection from the dead.”
Baptism is for a testimony or witness of Christ's resurrection; and we are baptized, εις, for the resurrection, in view of it, declaring it.
Baptism is for a testimony of our faith in a risen Lord, and our acceptance of him as our leader and Savior, and we are baptized, εις, for Christ, in view of this faith and acceptance, declaring it.
Baptism is for a testimony of remission of sins through him who has risen for - if Christ be not risen we are still in our sins, and we are baptized, εις, for the remission of sins, in view of it, declaring it.
John baptized, εις, for repentance, a testimony of the need of it or the fact of it; and they were baptized, εις, for repentance in view of it, declaring it.
“All our fathers,” says Paul, 1 Corinthians 10, "passed under the cloud and through the sea, and were all baptized", εις, unto Moses in the sea and in the cloud. It is the same word, εις, for which is here translated unto. This deep sea baptism through which the whole population passed was, εις, for a solemn witness that Moses was their accepted leader, in view of it, declaring it.
"Why then are we baptized for the dead?" asks the Apostle Paul, 1 Corinthians 15. The word for, here, though not εις in the original, involves the same idea. Baptism is a witness of the resurrection of the dead. Upon our faith in this we are baptized. It is for a testimony that the dead shall rise, it is for the resurrection, in view of it, declaring it.
“Who shall lay anything to the charge of God's elect?" says Paul in Romans 8. "It is Christ that died; yea, rather that is risen;" therefore, on account of his death, yea, rather of his resurrection we are justified, have remission, and none can lay anything to our charge. We are baptized, εις, for this glorious fact and for this wondrous blessing, the resurrection of Christ, the remission of sin.
Baptism for, in testimony of, in view of the remission of sins. This is, in brief, our view of the passage and a view, we think, which can be easily understood when presented to a popular audience.