Jesus answered him, "Because I told you, 'I saw you underneath the fig tree,' do you believe? You will see greater things than these!"
What are those greater things Jesus promised that Nathaniel would see?  (1) He had seen an example of Jesus' penetrating supernatural knowledge; but, in the future, he would see that knowledge employed in the achievement of human redemption, a far greater thing.  (2) He had seen the truth that Jesus is the Son of God; but, in the future, he would see Christ also as the Son of man and the achiever of reconciliation between God and all humanity.  (3) He had seen Jesus as King of Israel; but, in the future, he would come to know that Christ is not merely King of Israel, but King of all creation, King of kings, and Lord of lords  (1 Timothy 6:15).