Jesus described Nathanael as a true Israelite. He said there was no deceit (no dishonesty or trickery) in him.
This may contrast Nathanael with Jacob, whose early life was marked by deceit. Jacob later received the name Israel (see Genesis 25:27–34; 27:1–36; 32:22–32). In this way, Nathanael shows what God desires Israel to be. God wants his people to be an honest and faithful people.