In my denomination we baptize both infants and adults. It's a choice left up to the individual/parents based on their beliefs and interpretation of the texts. As an ordained minister, we may have our preferences, but we are supposed to agree to perform both types of baptism. And I appreciate the freedom. Their is evidence--both historically and biblically (whole families being baptized)--for both.
When a child or adult decides they want to be Infant baptism is done on the basis that is a sign of God's (prevenient) grace. His grace for us existed before we were even born and we can do nothing to earn it. Believer baptism is done as a response to deciding to follow God. Both are worthwhile expressions of faith. I was baptized as an infant. Our children were dedicated, and we have left it up to them to decide when they want to be baptized.
I have only had the privilege of officiating at one baptism for a good friend (for whom I also officiated her wedding). It truly is a privilege.
Repentance almost always precedes baptism in the New Testament. It was John's message about the Good News. In today's passage in Luke 3, John mentions that Jesus will baptize with the Holy Spirit and with fire. He gives the analogy of a farmer harvesting his wheat, separating the chaff from the grain and then burning the chaff.
I think because of burning images and other analogies of separating grain from weeds elsewhere, we tend to think of the chaff as sinners and the grain as believers. But the passage says Jesus will baptize with the fire. It is the recent repenter being baptized who is having the grain and chaff separated in their lives.
It was pointed out tonight that the farmer removed the chaff from the grain because it was the weeds and other things that grew up in the field that would have been poisonous (or at least very unappetizing) for the consumer to digest with the grain. Jesus desires to remove the poison in our lives when we repent of our sin.
Of course, we have to be willing to let go of that chaff and let it burn. It's not easy. A lot of it has been in our lives for a long time. But Jesus offers to separate it from the good in our lives and help us to get rid of it.
I think part of the reason why Jesus was baptized was because He needed it. Not to show penitence or as a witness to forgiveness or any religious reason; He needed to do it because it was a blessing to Him. When it was done, a voice came down from Heaven saying, "This is my Son with whom I am well pleased."
What an affirmation! Of course Jesus was ready to start His ministry after hearing that.
I think that's the witness for us as well. Yes, in baptism we identify with Christ dying and rising to new life. Yes, we give witness to our turning from sin, turning to God, and being forgiven. But we also are told, "You are my child. I am fully pleased with you." Isn't that something we need to hear?