Jesus’ opponents refused to accept his divine authority and claim to be the only Son from the Father. They demanded evidence for his Messianic claim and equality with God. Jesus answers their charges with the supporting evidence of witnesses. The Mosaic law had laid down the principle that the unsupported evidence of one person shall not prevail against a man for any crime or wrong in connection with any offence he committed (see Deuteronomy 17:6). At least two or three witnesses were needed. Jesus begins his defense by citing John the Baptist as a witness, since John publicly pointed to Jesus as the Messiah and had repeatedly borne witness to him (see John 1:19, 20, 26, 29, 35, 36). Jesus also asserts that a greater witness to his identity are the signs he performed. He cites his works, not to point to himself but to point to the power of God working in and through him. He cites God as his supreme witness.
Saint Augustine of Hippo says: “As Christians, our task is to make daily progress toward God. Our pilgrimage on earth is a school in which God is the only teacher, and it demands good students, not ones who play truant. In this school we learn something every day. We learn something from commandments, something from examples, and something from sacraments. These things are remedies for our wounds and materials for study.”