Final answer:
In response to Jesus saying 'Behold, an Israelite indeed, in whom is no deceit!' Nathanael asked how Jesus knew him, leading to his proclamation of Jesus as the Son of God and King of Israel after Jesus mentioned seeing him under the fig tree.
Step-by-step explanation:
When Jesus said, 'Behold, an Israelite indeed, in whom is no deceit!' Nathanael responded, 'How do you know me?' Upon which Jesus answered, 'Before Philip called you, when you were under the fig tree, I saw you.' Nathanael then declared, 'Rabbi, You are the Son of God! You are the King of Israel!' This exchange can be found in the Bible in the Gospel of John 1:47-49. It signifies Nathanael's recognition of Jesus's divine insight and his acknowledgment of Jesus's identity as the Messiah and the Son of God.