Luke 3 21-22 So Why Did Christ Get Baptized?
He was sinless. We all know that. Or at least, he'd never committed any sin, though tempted in every way.
But consider this. We come from God, who is Trinitarian in nature. Therefore, the reality that springs out of him (aka, us and creation) would "ontologically" (naturally) be Trinitarian in nature. That means everything is interconnected.
When Christ became flesh, he became part and parcel of a creation that had been infected with sin. And through no fault of his own, our sin became his. To say it like Paul did, "he became sin" (yes, no matter how we try to translate that away, 2 Corinthians 5:14 says that.
And he did that so we-- and all of the created order--might become the righteousness of God.
Once he did that, what happened next? Heaven was torn open, and free God WIFI (the Holy Spirit) was downloaded back into the created order. Or even better, He was shown to be with the created order visibly, as He had been all along.
So why did Christ get baptized? For us. Period. And to restore this truth.
We are God's beloved Children, whom He loves like crazy!