John 14:28
“You have heard Me say to you, ‘I am going away and coming back to you.’ If you loved Me, you would rejoice because I said, ‘I am going to the Father,’ for My Father is greater than I.”

We have discussed the doctrine of the Trinity in a number of places on this website. A corollary is that the Father is God, Jesus is God, and the Spirit is God—one God in three persons. A number of passages emphasize that Jesus is God (e.g., Philippians 2:5–8). Some people have stumbled over the phrase “being in the form of God,” as if this phrase implies a relationship that is less than equal. Actually, in the Greek, this phrase is even stronger than just saying “Jesus is God.” The phrase is closer to saying “Jesus manifests God.” The phrase states that Jesus and the Father are one in essence. Of course, John 1:1–3 points out that Jesus, the Word, created all things and so on.

Having accepted the deity of Christ, what are we to make of Jesus’s statement in John 14:28 that “My Father is greater than I”? Pseudo-Christian religions make much of this verse. For example, a Jehovah’s Witnesses publication called “What Does God Require of Us?” references this verse to “prove” that Jesus is inferior to God.¹

The misunderstanding here arises by confusing Christ’s divine nature with His human nature. Jesus is both fully human and fully God. J.C. Ryle puts it this way: “Trinitarians maintain the humanity of Christ as strongly as His divinity. . . . While Christ as God is equal to the Father, as man He is inferior to the Father.”² Calvin puts it similarly: “Christ does not now speak either of his human nature, or of his eternal Divinity, but, accommodating himself to our weakness, places himself between God and us.”³

This ties in with the Philippians passage in which we read that Jesus “made Himself of no reputation, taking the form of a bondservant, and coming in the likeness of men.” Simply put, in His humanity, Christ is lesser than God the Father. But in His deity He is equal. This explains why Mark 13:32 says that even the Son didn’t know something the Father did. As soon as we understand Christ’s dual nature, the alleged contradiction disappears.

In fact, this is the only way any of us can make any sense at all of the biblical language. On the one hand, there are distinct functions in the work of redemption voluntarily assumed by each member of the Godhead and expressed in language of deference and submission. On the other hand, there is perfect equality—each divine person sharing the same divine essence in an inter-trinitarian relationship. http://www.answersingenesis.org/articles/2009/04/13/contradictions-greater-than-or-equal-to