The "Christian Courier" has two excellent articles by Wayne Jackson concerning the use of the preposition "eis" in Greek. The first article deals with Acts 2:38 and the second with Matthew 12:41. From the article,

It has long been known that denominationalists, welded to the theory of salvation by “faith alone, ” repudiate the connection between baptism and the forgiveness of sins. Some, formally sound on this issue, now are capitulating to sectarian error. Take a brief look at this issue with us.