John 5: 30-40, Witnesses to the Messiah

Jesus, accused of abusing the Sabbath by healing a lame man, defends himself.  In his claims to be one with God, he identifies three witnesses to his identity as Messiah: John the Baptist, God ("the Father") and the Scriptures.

John 5: 30-40, Three witnesses to the Messiah's identity
By myself I can do nothing; I judge only as I hear, and my judgment is just, for I seek not to please myself but him who sent me.
31 “If I testify about myself, my testimony is not true. 
32 There is another who testifies in my favor, and I know that his testimony about me is true.

In general, testimony of this nature is expected to come from someone else.  Jesus will identify at least three witnesses, besides himself, to his Messianic claims.

John 5: 33-35, The witness of John the Baptizer
“You have sent to John and he has testified to the truth. 
34 Not that I accept human testimony; but I mention it that you may be saved. 
35 John was a lamp that burned and gave light, and you chose for a time to enjoy his light.

The first witness was John the Baptizer, who, as a "burning light" pointed the way to the Messiah. He provided "human testimony" that they personally watched and enjoyed his "light".

John 5: 36-38, The witness of the Father
“I have testimony weightier than that of John. For the works that the Father has given me to finish—the very works that I am doing—testify that the Father has sent me. 

37 And the Father who sent me has himself testified concerning me. You have never heard his voice nor seen his form, 

38 nor does his word dwell in you, for you do not believe the one he sent. 

The works of Jesus, given by the Father, offer God's testimony about Jesus.

And God has audibly spoken testimony about Jesus.  (Was this the voice at the baptism? Or is something more being mentioned here.

Those who don't want to hear, will not.  So the Jewish leaders are not aware of God's voice.

John 5: 39-40, The witness of Scripture

You study the Scriptures diligently because you think that in them you have eternal life. These are the very Scriptures that testify about me, 

40 yet you refuse to come to me to have life.

The Jewish Scriptures also provide testimony.  Jesus chastises his listeners for studying these Scripture and then ignoring them.

From the NIV footnotes: "You diligently study" in verse 39 could be an imperative, "Study diligently..."