What Was Nathanael Doing Under the Fig Tree?

Consider This Intriguing Question

Nathanael, believed to be the disciple Bartholomew, experienced a jarring first-encounter with Jesus. When the Apostle Philip called him to come and meet the Messiah, Nathanael was skeptical, but he followed along.

As Philip introduced him to Jesus, the Lord declared, "Here is a true Israelite, in whom there is nothing false." Immediately Nathanael wanted to know, "How do you know me?"

Jesus got his attention when he answered, "I saw you while you were still under the fig tree before Philip called you." Well, that stopped Nathanael in his tracks.

Shocked and surprised he declared, "Rabbi, you are the Son of God; you are the King of Israel."

So, what do you think Jesus saw under the fig tree that made Nathanael suddenly acknowledge him as the promised Savior?

Scholars can only speculate about this question, as the Bible doesn't say. Some believe Jesus had seen Nathanael's secret sin. This is my own pastor's theory, in fact. What's your theory?