1 What we have heard said by the Lord Jesus Christ to Nathanael, if we understand it aright, does not concern him only. For our Lord Jesus saw the whole human race under the fig-tree. For in this place it is understood that by the fig-tree He signified sin. Not that it always signifies this, but as I have said in this place, in that fitness of significancy, in which you know that the first man, when he sinned, covered himself with fig leaves. For with these leaves they covered their nakedness when they blushed for their sin; and what God had made them for members, they made for themselves occasions of shame.
For they had no need to blush for the work of God; but the cause of sin preceded shame. If iniquity had not gone before, nakedness would never have been put to the blush. For “they were naked, and were not ashamed.” For they had committed nothing to be ashamed for. But why have I said all this? That we may understand that by the fig-tree sin is signified. What then is, “when you were under the fig-tree, I saw you”? When you were under sin, I saw you. And Nathanael looking back upon what had occurred, remembered that he had been under a fig-tree, where Christ was not.
He was not there, that is, by His Bodily Presence; but by His knowledge in the Spirit where is He not? And because he knew that he was under the fig-tree alone, where the Lord Christ was not; when He said to him, “When you were under the fig-tree, I saw you;” he both acknowledged the Divinity in Him, and cried out, “You are the King of Israel.”
Source: Sermons on Selected Lessons of the New Testament (New Advent)