Baptism “for the forgiveness of sins” is a statement Peter makes in his sermon on the day of Pentecost (Acts 2:38). The preposition “for” comes from the Greek word “eis” which is defined by Strong’s to mean, “to or into (indicating the point reached or entered, of place, time, fig. purpose, result).”
There are those that argue the Bible translations should translate the Greek preposition “because of” instead of “for”. Understanding baptism to be “because of the forgiveness of your sins” would force a consequential change to the purpose of baptism. It would shift the forgiveness of sins to be something that happened before baptism, relegating the act to a pure ceremonial display.
It [Gr “eis”] is used over 1,700 times in the New Testament and it shows movement toward a goal. It indicates purpose. (radicallychristian.com)
When reviewing the actual Greek definition of “eis” and its use throughout Scripture, arguing for its translation to be “because of” is a stretch (to say the least). But what if those counter-arguments were less clear? What if the translation of “eis” were a little more vague or inconsistent? How would Scripture interpret Scripture in this case?