Final answer:
Jesus said He saw Nathanael before Philip called him in John 1:48, when Nathanael was under the fig tree. This moment is significant as it leads Nathanael to recognize Jesus's divine nature.
Step-by-step explanation:
The event where Jesus states that He saw Nathanael before Philip called him is found in the Gospel of John, specifically John 1:48. When Nathanael approaches, Jesus describes him as an Israelite in whom there is no guile. Nathanael asks how Jesus knows him, and Jesus replies, "Before Philip called you, when you were under the fig tree, I saw you."
This revelation astonishes Nathanael and leads him to recognize Jesus as the Son of God, the King of Israel. This passage illustrates Jesus's omniscience, a trait attributed to his divine nature, and it firmly establishes the foundation of faith for Nathanael.