If Jesus is God, then why did He say the Father was greater than He?

"You heard that I said to you, ‘I go away, and I will come to you.’  If you loved Me, you would have rejoiced, because I go to the Father; for the Father is greater than I,'" (John 14:28).

Jesus said the Father was greater than He not because Jesus is not God, but because Jesus was also a man and as a man he was in a lower position.   He was ". . . made for a little while lower than the angels . . ." (Heb. 2:9).  Also in Phil. 2:5-8, it says that Jesus "emptied Himself, taking the form of a bond-servant, and being made in the likeness of men . . ."

Jesus has two natures:  divine and human.  Jesus was not denying that He was God.  He was merely acknowledging the fact that He was also a man.  Jesus is both God and man.  As a man, he was in a lesser position than the Father because he had added to Himself human nature (Col. 2:9) and was made under the Law (Gal. 4:4).  He became a man to die for people (1 Cor. 15:1-4).

A comparison of difference of position can be found in the marriage relationship.  Biblically, a husband is greater in position and authority than his wife. He is her head (Eph. 5:23).  But, he is no different in nature and he is not better than she.  They share the same nature, being human, and they work together by love and commitment to the Lord.

So, Jesus was not denying that He was God.  He was simply acknowledging that He was also a man and as a man, he was subject to the laws of God so that He might redeem those who were under the law; namely, sinners (Gal. 4:4-5).