What’s Necessary for Baptism?

Have thought long and hard about who to baptize, when to baptize, and re-baptizing.   Stumbled upon this quote as I again was reflecting on these issues when we baptized fourteen people a week ago!

Many of us came to faith and were baptized at a point when we did not know very much. This is good. It is expected that baptism happens early in the Christian walk when you do not know very much. So it is also expected that you will learn later more and more of what it means.
Don’t think, “Oh, I must go back and get baptized again. I didn’t know it had all this meaning.” No. No. That would mean you would be getting re-baptized with every new course you take in Biblical theology. Rather, rejoice that you expressed your simple faith in obedience to Jesus and now are learning more and more of what it all meant.  -John Piper Sermon, What Baptism Portrays