From the gospel according to John, chapter one:
43 The next day Jesus decided to go to Galilee. He found Philip and said to him, “Follow me.” 44 Now Philip was from Bethsaida, the city of Andrew and Peter. 45 Philip found Nathanael and said to him, “We have found him about whom Moses in the law and also the prophets wrote, Jesus son of Joseph from Nazareth.” 46 Nathanael said to him, “Can anything good come out of Nazareth?” Philip said to him, “Come and see.” 47 When Jesus saw Nathanael coming toward him, he said of him, “Here is truly an Israelite in whom there is no deceit!” 48 Nathanael asked him, “Where did you get to know me?” Jesus answered, “I saw you under the fig tree before Philip called you.” 49 Nathanael replied, “Rabbi, you are the Son of God! You are the King of Israel!” 50 Jesus answered, “Do you believe because I told you that I saw you under the fig tree? You will see greater things than these.”
The otherwise excellent commentary by Raymond Brown wrestles a bit with Jesus’s greeting to Nathanael, suggesting that perhaps “in whom there is no deceit” is a play on a popular false etymology of “Israel” as meaning that one sees clearly.
I suspect Brown was missing the forest for the trees here. Nathanael has snarkily rejected any pretensions on Jesus’s part, either because the Messiah isn’t supposed to come from Nazareth, or because Nazareth was just facially unlikely, like Pearl, Mississippi. We know from the passage that Jesus saw Nathanael under the fig tree; presumably he also knew Nathanael’s remark, and is making a quip about it.
Never overlook the possibility that Jesus had a sense of humor; it can mislead the overly grave interpreter.