Baptism is the work of God, not man. It is not a sign of the believer’s commitment to God (which would, therefore, require prior faith and repentance), but the sign and seal of God’s promise to save all who do not reject their baptism by refusing to trust in Christ. For the nature of baptism, see Mark 16:16, Acts. 22:16; Rom. 6:3; Tit. 3:5. The reason these references are to those who have first believed is that the first converts, obviously, were adults when the believed, but they evidently baptized their children. The same was true of Abraham, who believed before he was circumcised, but then had his children circumcised as infants.

via Alliance of Confessing Evangelicals.