Jesus was without sin, yet He chose to be baptized. This was not because He needed cleansing, far from it. Through careful study of the person of Jesus Christ we learn that He is one that is very much concerned about doing God's will and nothing else. Nothing else matters to Him than the will of His father.
Even when Jesus approached John the Baptist to get Him baptized John initially refused. But Jesus insisted it be done. He understood that God’s plan is not always about what we need, but about fulfilling all righteousness. Jesus chose to obey and set a good example despite His status.
By being baptized, Jesus set an example for all who would follow Him. Through His act we get to understand that obedience is not only for sinners seeking forgiveness, but for believers who are intentional to the purpose of God. When we start to refuse God's will because we feel we are “above it” then we have missed it.
If the sinless Son of God humbled Himself to obey, then we have no excuses to give. none of us has a reason to resist God’s direction. True discipleship is proven in submission. Righteousness is not evident if submission cannot be found.