"If I testify on my own behalf, my testimony cannot be verified. But there is another who testifies on my behalf, and I know that the testimony he gives on my behalf is true. You sent emissaries to John, and he testified to the truth. I do not accept testimony from a human being, but I say this so that you may be saved. He was a burning and shining lamp, and for a while you were content to rejoice in his light. But I have testimony greater than John's. The works that the Father gave me to accomplish, these works that I perform testify on my behalf that the Father has sent me. Moreover, the Father who sent me has testified on my behalf. But you have never heard his voice nor seen his form, and you do not have his word remaining in you, because you do not believe in the one whom he has sent. You search the scriptures, because you think you have eternal life through them; even they testify on my behalf. But you do not want to come to me to have life. "I do not accept human praise; moreover, I know that you do not have the love of God in you. I came in the name of my Father, but you do not accept me; yet if another comes in his own name, you will accept him. How can you believe, when you accept praise from one another and do not seek the praise that comes from the only God? Do not think that I will accuse you before the Father: the one who will accuse you is Moses, in whom you have placed your hope. For if you had believed Moses, you would have believed me, because he wrote about me. But if you do not believe his writings, how will you believe my words?" (Jn 5:31-47)
To the unbelieving crowd Jesus is presenting witnesses. Earlier there was another witness to Jesus: John the Baptist. People considered John the Baptist as prophet and they listened to him gladly and he also bore witness to Jesus. But the crowd has not accepted his witness otherwise they would have followed him.
Now Jesus is offering other witnesses. They are his own preaching and his doings (miracles). All these works were given commissioned by God. Works were the proofs that Jesus himself was sent by God. God had borne witness to Jesus. Jews say that they search the scriptures to find eternal life and even the scriptures bear witness to Jesus. Witnesses are from the deeds of Jesus, from god himself, and Scriptures.
The Jews believed in Moses. They believed that the words of Jesus would be fulfilled and they will receive eternal life through the words of Jesus. But Moses himself spoke about Jesus and the works of Jesus and the salvation through Jesus. Witnesses were in abundance but the heart of the people were not ready and willing.
