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. Peter said unto them, Repent - Μετανοησατε; Humble yourselves before God, and deeply deplore the sins you have committed; pray earnestly for mercy, and deprecate the displeasure of incensed justice. For a definition of repentance, see on Matthew 3:2 (note).
And be baptized every one of you - Take on you the public profession of the religion of Christ, by being baptized in his name; and thus acknowledge yourselves to be his disciples and servants.
For the remission of sins - Εις αφεσιν ἁμαρτιων, In reference to the remission or removal of sins: baptism pointing out the purifying influences of the Holy Spirit; and it is in reference to that purification that it is administered, and should in consideration never be separated from it. For baptism itself purifies not the conscience; it only points out the grace by which this is to be done.
Ye shall receive the gift of the Holy Ghost - If ye faithfully use the sign, ye shall get the substance. Receive the baptism, in reference to the removal of sins, and ye shall receive the Holy Ghost, by whose agency alone the efficacy of the blood of the covenant is applied, and by whose refining power the heart is purified. It was by being baptized in the name of Christ that men took upon themselves the profession of Christianity; and it was in consequence of this that the disciples of Christ were called Christians.