6 Let no one then suppose that Baptism is merely the grace of remission of sins, or further, that of adoption; as John's was a baptism conferring only remission of sins: whereas we know full well, that as it purges our sins, and ministers to us the gift of the Holy Ghost, so also it is the counterpart of the sufferings of Christ. For this cause Paul just now cried aloud and said, Or are you ignorant that all we who were baptized into Christ Jesus, were baptized into His death? We were buried therefore with Him by baptism into His death. These words he spoke to some who were disposed to think that Baptism ministers to us the remission of sins, and adoption, but has not further the fellowship also, by representation, of Christ's true sufferings.
Source: Catechetical Lectures (New Advent)