He is Son, and he has made himself 'servant'!
Today's liturgy speaks explicitly of this in the words of the book of Isaiah: "Behold my servant whom I uphold, / my chosen one in whom I am well pleased, / I have set my spirit upon him; / he shall bring forth the right to the nations" (Is 42:1).
Jesus Christ: Son who became a servant. The Baptism in the Jordan fully reconfirms this: Jesus presents himself to John to be baptised; but the latter tries to prevent him by saying: "I need to be baptised by you and you come to me?" (Mt 3:14).
As if he wanted to say: "You who are the bearer of saving Grace and Lord of our salvation". Jesus, however, replies: "Let it be for now, for thus we fulfil all righteousness" (Mt 3:15).
Jesus receives Baptism from John: the Baptism of Penance. In this way he manifests himself as the servant of our redemption. He comes as the Lamb of God, who takes away the sin of the world (cf. Jn 1:29, 36). He bears within himself the will of obedience to the Father even unto death.
He comes as the one who "will not break a cracked reed, / will not quench a wick with a dull flame" (Is 42:3).
[Pope John Paul II, Angelus 13 January 1985]