The whole Christian gospel could be summed up in this point: that when the living God looks at us, at every baptized and believing Christian, he says to us what he said to Jesus on that day. He sees us, not as we are in ourselves, but as we are in Jesus Christ. It sometimes seems impossible, especially to people who have never had this kind of support from their earthly parents, but it’s true: God looks at us, and says, ‘You are my dear, dear child; I’m delighted with you.’ Try reading that sentence slowly, with your own name at the start, and reflect quietly on God saying that to you, both at your baptism and every day since.
It is true for one simple but very profound reason: Jesus is the Messiah, and the Messiah represents his people. What is true of him is true of them. The word ‘Messiah’ means ‘the anointed one’; and this story tells how Jesus was anointed with the Holy Spirit, marked out as God’s son. The Messiah is called ‘God’s son’ in a few biblical passages, including the one that the heavenly voice seems to be echoing here (Psalm 2:7). Thought the early Christians realized quite quickly that Jesus was God’s son in an even deeper sense, they clung on to his messiahship for dear life. It was because Jesus was and is Messiah that God said to them, as he does to us today, what he said to Jesus at his baptism. And without that word from God all we often hear, in our mind’s ear, is doors being slammed.”
– N.T. Wright, “Mark for Everyone”