-- Answer: Jesus --

Yes, it was the Lord Himself who stated in Mark 16:16 that "He that believeth and is baptized shall be saved...."

Surely, if this were the only verse in all the Bible that placed baptism in connection with salvation, that would suffice -- but it is not! There are various others that also remain consistent to this truth: people must be baptized in order to...

* be saved (1 Peter 3:21)
* receive the "remission of sins" (Acts 2:38)
* "wash away" sins (Acts 22:16)
* "walk in newness of life" (Rom. 6:4)

...just to name a few.

Throughout the New Testament, water baptism is seen as part of the plan to have sins forgiven and become a Christian, which is all in harmony with what Jesus declared in Mark 16:16 that "He that believeth and is baptized shall be saved...."