If Jesus is God, then why does he say "The Father is greater than I"?

Muslims often point out that Jesus is not God because he said, "The Father is greater than I".
To them this is proof that Jesus is not divine.

You have heard Me tell you, 
‘I am going away and I am coming to you.’ 
If you loved Me, you would have rejoiced that I am going to the Father, because the Father is greater than I.
--John 14:28

And yet one wonders why Jesus had to point this out.  I know that I have never felt the need to clarify on this point.

If this means that Jesus was only a human prophet then what does it mean three chapter later Jesus prays:

And now, O Father, glorify thou me with thine own self with the glory which I had with thee before the world was.
--John 17:5

This says that Jesus had glory along side the Father in eternity.  How can this be?

Let each of you look not only to his own interests, but also to the interests of others. Have this mind among yourselves, which is yours in Christ Jesus, who, though he was in the form of God, did not count equality with God a thing to be grasped, but emptied himself, by taking the form of a servant, being born in the likeness of men. And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross. Therefore God has highly exalted him and bestowed on him the name that is above every name, so that at the name of Jesus every knee should bow, in heaven and on earth and under the earth, and every tongue confess that Jesus Christ is Lord, to the glory of God the Father.
--Philippians 2:4-11

Most scholars agree that Paul is quoting an early Christian hymn in this passage.

Here is a video that answers this by Sam Shamun:
https://youtu.be/VzBesvLK5bE