Q. Why was God pleased with Jesus at his baptism? What had Jesus done at that point? Jesus had only been baptized, he had not started his ministry, but the heavens opened and God said, “This is my Son, whom I love; with him I am well pleased.”
I don’t think we should completely rule out the possibility that God the Father was saying that He was pleased with who Jesus had become to that point in his earthly life. Luke tells us that in Jesus’ youth and young adulthood, he “grew in wisdom and in stature and in favor with God and all the people.” So the Father could have been expressing His pleasure in Jesus’ godly character and spiritual maturity; Jesus had prepared well for the ministry he was just about to begin.
However, it’s important to realize that the language of being “pleased with” someone is actually the language of choice or selection in the Greek of the New Testament and the Septuagint (a Greek translation of the Old Testament that was widely used in the time of Jesus and the apostles). For example, there’s actually an extra psalm in the Septuagint. It’s considered Psalm 151 and it’s attributed to David, although its authorship is actually uncertain. But in it, the character of David describes how he became king. He says that the Lord’s messenger (that is, Samuel) “took me from my father’s sheep and anointed me with his anointing oil.” He adds, “My brothers were handsome and tall, but the Lord was not pleased with them.” This doesn’t mean that that the Lord didn’t like them. Rather, David is saying, “The Lord didn’t choose them instead of me.”
And so we should understand that when the Father says He is “well pleased” with Jesus at his baptism, He means in the same way, “This is the one I have chosen to be my Messiah.” As Gottlob Schrenk writes in The Theological Dictionary of the New Testament, “What is meant is God’s decree of election, namely, the election of the Son, which includes his mission and His appointment to the kingly office of Messiah.”
We find confirmation of this understanding later in the gospel of Matthew when the Father’s declaration at Jesus’ baptism is echoed in a quotation from the book of Isaiah:
Here is my servant, whom I have chosen,
the one I love, in whom I delight;
I will put my Spirit on him,
and he will proclaim justice to the nations.
Here the idea of being delighted in (i.e. having someone pleased with you) is used in exact parallel with the idea of being “chosen.” We also see again that the use of this phrase is accompanied by the gift of the Spirit for mission, just as in the case of Jesus’ baptism.
So while the Father was no doubt pleased by the way Jesus had matured into godly character in preparation for his ministry, the phrase “with him I am well pleased” actually indicates how God has chosen Jesus to be the Messiah.
Good Question 
Could there be more than God just being pleased that HE had chosen Jesus or have chosen Jesus.
What was the real reason for Jesus baptism> was it not “to fulfill all righteousness”. This is what Jesus told John the Baptist, so what is unrighteousness> SIN> What is righteousness? NO SIN.
The picture reflecting Jesus baptism, is it not predicting the wrong message> If we look at Mathew Mark Luke we see that the Holy Spirit rested upon when Jesus left the water onto dry land? The Holy Spirit came upon Jesus when HE left the water?
Your comments appreciated
Regarding Jesus fulfilling all righteousness, see this post. As for the image of Jesus’ baptism, it’s simply the artistic license of the designer to depict the dove of the Holy Spirit above Jesus while he is still in the water. A painting isn’t supposed to be as realistic as a photograph; it’s an interpretation of its subject matter. It’s actually the standard composition over the history of sacred art to have Jesus in the center in the water, John on the right with his hand raised above Jesus’ head, angels on the left, and the dove above Jesus. See this image for example (Verrocchio, “The Baptism of Christ,” c. 1475, with some details by his pupil Leonardo da Vinci):
I find it interesting to note the comparison between the pleasure of God with Jesus (the true Israel) and the people of ancient Israel, with many of whom He was NOT pleased, and their bodies were strewn in the wilderness. The body of Jesus, though disfigured beyond recognition, was raised from the dead, glorified, after 3 days. The people of God today, can choose to be identified with the world, and be destroyed with the world. Or they can choose to identify with Jesus, with whom God was well pleased, and find that God is well pleased with them, despite their shortcomings, and are promised resurrection and glorification, instead of perishing, like the people of Israel, who despite being God’s chosen people, perished in the wilderness, never entering the promised land.
Hi Jesus was baptised by John the Baptist. What was the reason, for Jesus baptism? ‘to fulfill all righteousness”. What is sin “unrighteousness” therefore Jesus baptism was to take away sin. If we look at how the sins of Isreal were taken away it was where the high priest, placed his hands on the head of the sacrificial goat and transfer all the sins unto the goat, the goat never become a sinner it only carried the sin, then it was lead into the wilderness by a capable man. What did the people see, they saw their sins being taken away. Now if Jesus is the replica of how sins were taken away, if John the baptist the greatest of all in the old testament, then being a high priest John laid his hands on Jesus and transferred all the sins of the world unto Jesus. That is why God was pleased with his son Jesus. What happened after Jesus baptism the was also led into the desert by the Holy Spirit to be tempted by Satan. What was the offence sin, as wages of sin is death, Jesus carried our sins and therefore the had to pay penalty(death).
Now sin came then Jesus dealt with sin once and for all time. so did Jesus death on the cross did not give us eternal life, it only settled sin, JESUS RESURRECTION GUARANTEES US ETERNAL LIFE, that is why it says death were is your sting.