49 For I have not spoken of myself; but the Father which sent me, he gave me a commandment, what I should say, and what I should speak.
50 And I know that his commandment is life everlasting: whatsoever I speak therefore, even as the Father said unto me, so I speak.
John 12:49-50 (KJV)
Jesus was declaring that God his Father had spoken to him, and had put the words in his mouth that he was to speak.
8 For I have given unto them the words which thou gavest me; and they have received them, and have known surely that I came out from thee, and they have believed that thou didst send me.
John 17:8 (KJV)
In John 17:8 Jesus is making a declarition that he had finished the work God his Father had given him to do on earth, which was to give us the words of God his Father exactlly in the same words the Father gave them to him.
32 Then Jesus said unto them, Verily, verily, I say unto you, Moses gave you not that bread from heaven; but my Father giveth you the true bread from heaven.
33 For the bread of God is he which cometh down from heaven, and giveth life unto the world.
34 Then said they unto him, Lord, evermore give us this bread.
35 And Jesus said unto them, I am the bread of life: he that cometh to me shall never hunger; and he that believeth on me shall never thirst.
36 But I said unto you, That ye also have seen me, and believe not. John 6:32-36 (KJV)
Jesus is giving a warning that the words given by Moses did not come from God the Father.
John 5:37 and John 1:17-18 are 2 more warnings that the words spoken by Moses did not come from God the Father.
John 3:14-15 and Rev 12:9 tell the reader where Moses really did get the words he spoken from.