A baptism is one of the most beautiful things I have ever seen; someone dedicating their lives to God, declaring Jesus as their Lord and Savior and starting their journey as a new creation!
I was reading Matthew 3 and something John the Baptist really got me thinking about baptisms. In verse 11 he said, "I indeed baptize you with water unto repentance, but He who is coming after me is mightier than I, whose sandals I am not worthy to carry. He will baptize you with the Holy Spirit and fire."
Here we have John, a preacher, performing a water baptism "unto repentance" and talking about Jesus ("He") who will baptize with the Holy Spirit and fire.
A water baptism done by a pastor is a public declaration of you declaring yourself to be a sinner and accepting Jesus Christ as your Lord and Savior, Romans 10:9 being practiced in a public display of you being a new, born again creation. This is salvation.
Now let's talk about the baptism by fire. As we continue reading Matthew 3, verse 12 says (He will) gather His wheat into the barn; but He will burn up the chaff with unquenchable fire.” When we look at crop, corn or wheat, it's made up of the actual grain and the chaff. The grain is the useful part, the actual crop and the chaff is the useless part, the hull or the husk which needs to be discarded. In this verse John is trying to say that we are the wheat or grain (the useful part of a crop) and the Holy Spirit burns away the old sinful creation which is the chaff (the useless hull). This is sanctification.
Throughout the Bible we see references about grain/corn and chaff so next the time we think or watch a baptism, remember that God is not just showing us someone being saved, but you're seeing an actual birth - a spiritual birth with the person being reborn into a new creation.