John 3:22-36

After this Jesus and his disciples went into Judea, where he spent some time with them and was baptizing. John was baptizing at Aenon near Salem because there was a lot of water there, and people were coming to him and being baptized. (John hadn’t yet been thrown into prison.)

A debate started between John’s disciples and a certain Jew about cleansing rituals. They came to John and said, "Rabbi, look! The man who was with you across the Jordan, the one about whom you testified, is baptizing and everyone is flocking to him."

John replied,"No one can receive anything unless it is given from heaven. You yourselves can testify that I said that I'm not the Christ but that I’m the one sent before him. The groom is the one who is getting married. The friend of the groom stands close by and, when he hears him, is overjoyed at the groom’s voice. Therefore, my joy is now complete. He must increase and I must decrease. The one who comes from above is above all things. The one who is from the earth belongs to the earth and speaks as one from the earth. The one who comes from heaven is above all things. He testifies to what he has seen and heard, but no one accepts his testimony. Whoever accepts his testimony confirms that God is true. The one whom God sent speaks God’s words because God gives the Spirit generously. The Father loves the Son and gives everything into his hands. Whoever believes in the Son has eternal life. Whoever doesn’t believe in the Son won’t see life, but the angry judgment of God remains on them."
(CEB)

One of the challenges of translating certain passages is that it isn't always clear where the quotation marks belong because in the original Greek text that John's Gospel was written in didn't include quotation marks.  In most cases, a plain reading in context points to where the quotes should go.  But sometimes it isn't so easy.

Take a look again at this passage and see how John the Baptist starts speaking "No one can receive anything unless ... "  In this translation, the quote goes all the way out to " ... the angry judgment of God remains on them."

Is it possible that the quote ends earlier and the latter part is "commentary" by John the Apostle?

For example, check out the ESV, TNIV and NRSV translations of the text where John the Baptist quote is ended with his statement  He must increase and I must decrease. 

Indeed, that does sound like a logical place for John the Baptist to have stopped speaking?

What was John the Baptist's message?

John the Baptist points toward Christ by explicitly saying he is NOT the Christ but the one sent before Him.  John the Baptist then uses the analogy of the difference between the Groom and the friend of the Groom.  He wraps up by declaring:  Therefore, my joy is now complete. He must increase and I must decrease. 

At this point, it is possible that John the Baptist elaborated further.  But equally possible is that John the Apostle picks up the ideas but uses themes already introduced in the earlier parts of the Gospel to extend the conversation beyond John the Baptist's remarks. 

The one who comes from above is above all things. The one who is from the earth belongs to the earth and speaks as one from the earth. The one who comes from heaven is above all things. He testifies to what he has seen and heard, but no one accepts his testimony. Whoever accepts his testimony confirms that God is true.

The "above" type language is straight from the mouth of Jesus in the earlier parts of John 3.  The "heaven" image has been used previously by Jesus John 3:13 and John the Baptist in John 3:31.  The "testify" motif shows up in John 1:7-8, 2:25, 3:11.  Almost all of these reference back to something connected to the divine nature of Jesus.

John the Apostle round out the commentary by drawing upon the majesty and the mystery of the Trinity in how God speaks through the sending of His Son and the giving of the Holy Spirit and the need to believe/trust in the Son. This kind of language makes a whole lot more sense post Pentacost - when the Holy Spirit was poured out upon the Church after the Resurrection and Ascension that would not have been available to John the Baptist.

The one whom God sent speaks God’s words because God gives the Spirit generously. The Father loves the Son and gives everything into his hands. Whoever believes in the Son has eternal life. Whoever doesn’t believe in the Son won’t see life, but the angry judgment of God remains on them.

How is this rather "theological" section applicable to daily life?

I think we can definitely take John the Baptist's example of not taking the spotlight but instead point to Jesus the Christ. We really need a God is God and I am not attitude in life.  And after we have by our life and deeds and words, pointed to Christ, we leave it to God since He is the one who gives the Spirit that works mysteriously, invisibly and sometimes/sometimes not subtly like the wind to change people's lives.

Lord, help me to trust in your Son and step into eternal living each day.  Help me to decrease so that you may increase.  Help me to point people to you.  Amen