John 5:30 I can of Myself do nothing. As I hear, I judge; and My judgment is righteous, because I do not seek My own will but the will of the Father who sent Me.
Christ is not a law unto Himself as many like to think they are but is part of the Trinity. In order for the Trinity to be the truth they have to agree on and about everything.
What Christ hears, not from men but from God the Father, He retells and uses to show others.
Christ is not seeking to puff Himself up but to lift up the name of Christ instead. When we get to hear what Christ has said, we can be sure that those words came from God and not just from His own lips.