In presenting himself to the religious leaders, Jesus used the kind of legal evidence that they should have been able to understand. He explained how, and why he performed the miracles he was rapidly becoming known for doing.

Getting started in , Keith, Nathan, and our usual resource in digging into the Bible, J Vernon McGee take turns to comment.

30 "I can do nothing on my own. As I hear, I judge, and my judgment is just, because I seek not my own will but the will of him who sent me.
Jesus didn't do anything just because he felt like it. Everything he did was the father's will. Because his every action was filtered by the father, his judgements were always right,.
31 If I alone bear witness about myself, my testimony is not true.

Not that testimony isn't true, but to prove it legally true takes a second supporting testimony. It would still be true while waiting for the additional support. A challenge from the Big Book of Bible Difficulties helps to respond to the problem of this statement Jesus makes.
32 There is another who bears witness about me, and I know that the testimony that he bears about me is true.
Jesus points out that he knows of the required second witness. who is this second witness he knows about? Is it the Holy Spirit, or John. The Baptist? There's some disagreement among bible experts, but based on following statements, probably John.
33 You sent to John, and he has borne witness to the truth.
The truthful witness is John the Baptist. Religious leaders had already sent to him, 1:19. Just before Jesus baptism. already having John's witness, Jesus admission would confirm the truthfulness of his statement.
34 Not that the testimony that I receive is from man, but I say these things so that you may be saved.
Jesus doesn't need earthly confirmation. For those who believe the truth of who he is, his words have eternal consequence. However, he seems to be going through the legal motions to offer proof they might recognize or allow. His words have purpose, to save, even these doubtful religious leaders.
35 He was a burning and shining lamp, and you were willing to rejoice for a while in his light.
Speaking of John the Baptist, the past tense might imply that John was not only in captivity, but already executed. John seems widely accepted as a bright lamp of truth among even the religious elite. Widely accepted, if not understood.
36 But the testimony that I have is greater than that of John. For the works that the Father has given me to accomplish, the very works that I am doing, bear witness about me that the Father has sent me.
The real testimony is in Jesus works. His actions prove his power and authority. When John needed proof, Jesus healed and did signs, then told John's disciples to report what they saw. Jesus didn't do miracles to glorify himself, but to demonstrate his authority. Anybody can make a claim. Actions back it up,

"Used with permission from Microsoft."
37 And the Father who sent me has himself borne witness about me. His voice you have never heard, his form you have never seen,
The voice of man testified. John,. Jesus own works testified, signs. Now he claims God himself testifies. Through the body of the prophets, law, and scripture. The religious leaders had never seen or heard a voice and physical form . Did they never pay attention to it? Or did they never come close to experiencing it?

An answer coming up.
38 and you do not have his word abiding in you, for you do not believe the one whom he has sent.

Clearly they did their religious deeds apart from God's endorsement. If god did abide (live) with them, it would be easy to recognize his actions in Jesus. God's spirit in them should cause them to recognize the same spirit in Jesus.