If Jesus is God, then why did Jesus say that the Father is greater than I in John 14:28?
“You heard me say, ‘I am going away and I am coming back to you.’ If you loved me, you would be glad that I am going to the Father, for the Father is greater than I.
John 14:28
The doctrine of the trinity clearly teaches that the Father, Son and the Holy Spirit are indeed God. One God manifested in three persons. Our human minds cannot fully grasp the greatness of God on many levels, and the trinity is a difficult challenge.
How could Jesus who is God make the claim that the Father is greater than him? Ask yourself this question: how could Jesus, being God, chosen to take on human flesh, being born as a baby, crying when hungry, as a toddler, learning to walk, growing as a boy, skinning his knee and feeling pain, getting the flu and feeling sick and yet be God? In the redemption of man, Jesus had to be fully human and fully God. And in his role as human, God the Father is greater than God the Son. Or simply put, Jesus as God is equal to the Father and as man he is lesser to the Father.
The same type of situation is found in the gospel of Mark.
But about that day or hour no one knows, not even the angels in heaven, nor the Son, but only the Father.
Mark 13:32
Jesus is talking about the end times in this verse. How could God the Father know something that God the Son does not. When we understand the dual nature of Christ being fully God and fully human then these passages become clear.