John 5:31

If I bear witness of myself, my witness is not true.

Jesus spoke these words in the discourse that followed His healing of the paralytic, the impotent man, at Bethesda, at the pool of Bethesda, on the Sabbath, when the Jews accused Him of breaking the Sabbath, in the temple controversy. He had purposely chosen the Sabbath for the healing to free the day from the restrictions heaped upon it by the Jews. In answering the accusation of Sabbath-breaking He claimed equal rights with God to do a work equally sacred and of the same character as the work of the Father in heaven. This incensed the Pharisees as Sabbath-breaking and as making Himself equal with God.

His relationship with God forbade Him to work independent of the Father or against His will. He sought the Father's will, not His own, and His judgment was therefore just. His own testimony about Himself is not presented as sufficient proof on its own, so He did not ask His hearers to accept a claim supported only by His own testimony but bound His assertions with other testimonies borne of Him. This need for other testimony follows His declaration of His work in connection with the Father, because human knowledge cannot reach the courts of heaven to witness concerning the mysterious connection of Jesus with the Father.

The greater witness is the work the Father gave Him to do, including the works He performed, which declare His divinity and testify that the Father had sent Him. The Father also testified at His baptism with wonderful manifestations of God. John testified to the truth and identified Jesus as the Christ, the Redeemer of the world, the Son of God, the one sent by God. His mission was solely to prepare the way for Jesus, and another witness confirms who Jesus is and that His testimony is true, which Jesus knew was true. The Jewish leaders had for a season accepted John as a prophet of God and rejoiced in his light, and had sent to him and received his statement of the baptism of Jesus.

He did not refer to John's testimony to establish or sustain His own claims and identity. He referred to it only so His hearers, persecutors, and rulers could recognize their blindness and inconsistency in rejecting and opposing Him whom John declared to be the Son of God, which could lead them to salvation. The verse teaches that man is inseparably bound to his heavenly Parent, responsible to God who holds all destinies, appointed and endowed to do God's work. While faithful to that stewardship man is warranted in claiming his Master's blessings and promises, but when exalted in self, depending on his own wisdom and power and separating from God, he is called to account for unauthorized acts.