"The Jews there were amazed and asked, “How did this man get such learning without having been taught?”
Jesus answered, “My teaching is not my own. It comes from the one who sent me. Anyone who chooses to do the will of God will find out whether my teaching comes from God or whether I speak on my own. Whoever speaks on their own does so to gain personal glory, but he who seeks the glory of the one who sent him is a man of truth; there is nothing false about him."
Jesus basically says that if you're questioning his teaching then ask God, if you honestly ask God he will let you know that Jesus' teaching is real.
Jesus taught that he and God are one. So God will tell you - or show you - that Jesus is God.
There's no way to explain that, but I ask you this Christmas time, if you don't believe in God, or if you believe in God but think Christianity with this Jesus guy is a bit far fetched... honestly open yourselves up to asking God if he is real - and if Jesus is the key part of him. Because if you do then I know God will show you Jesus is Lord.
Contact me if you want to ask anymore questions, but first, ask God (that's the start of doing his will) and you will find out that Jesus' teaching comes from God.