It does seem a little odd, doesn’t it?
John’s mission was to announce Christ’s coming, to preach repentance for sins and conversion, to baptize people as a way of cleansing them of their sins and when Jesus appears on the scene, He shows up in line to be baptized.
But Jesus wasn’t a sinner – he never sinned! He didn’t need to repent, so why should he be baptized?
It makes sense that John would object, but Jesus insists, and John Baptizes him anyway. What was the point?
The point is that the Word became flesh and dwelt among us. Why? Because he loves us. It really is that simple.
God did not choose to save us from afar. He lived among the sinners he came to save. Jesus saved us by becoming one of us. He suffered with us and for us. He conquered death by dying for us. He overcame sin by living among sinners.
His baptism is a preview of everything that is to come.
By getting baptized along with sinners, Jesus expressed his desire to take our place, to take the punishment for our sins upon himself, so as to free us from them.
On the cross, that is what he actually did: he took upon himself the sins of the world. That was the very reason he came into this world.
And he continues his saving mission in the Church today, through the sacraments. We are truly cleansed from sin in baptism, where we die to our old self and arise with Christ to new life in him. He continues to forgive our sins when we repent for them in the sacrament of reconciliation. And he abides with us and nourishes our souls in the Eucharist, where he is truly present.
All seven sacraments are gateways to heaven, where Jesus enters our lives, touches us, heals us, and saves us. His being baptized by John is consistent with how he manifests all his saving power – he holds nothing back and goes all the way only out of sheer love for us.
When we participate in the sacraments, he not only manifests but fully exercises the same power, and we show our faith and full commitment to him in return.