Commonly regarded as the same person as the apostle Bartholemew, Nathaniel already possessed an honest heart when Philip told him about Jesus (John 1:43-51).
Bishop Ryle says of him: ‘Nathanael, there can be no doubt, was a true child of God, and a child of God in difficult times. He was one of a very little flock. Like Simeon and Anna, and other pious Jews, he was living by faith and waiting prayerfully for the promised Redeemer, when our Lord's ministry began. He had that which grace alone can give, - an honest heart, a heart without guile.’
John tells us that Jesus had his eye on Nathaniel before they met. The Saviour mentions that he saw Nathaniel under a fig tree. This was a common way of describing meditation on the things of God. Nathaniel was amazed that Jesus knew this detail about him, perhaps because he engaged in it privately. Jesus commended Nathaniel for his meditation and maybe discussed the particular passage of his thoughts when speaking about Jacob and his dream.
Albert Barnes says of this awareness of Jesus ‘that he judges of our character chiefly by our private devotions. Those are secret; the world sees them not; and in our closets we show what we are. How does it become us, therefore, that our secret prayers and meditations should be without "guile" and hypocrisy, and such as Jesus will approve!’
Moreover, Nathaniel possessed an ability to absorb spiritual truth quickly as seen in the names he uses for Jesus. As he interacted with Jesus here, he was able to put things together from Old Testament passages and so confess that Jesus is a teacher, a divine person, and the Messiah of Israel. Is there a connection between his speedy grasp and his regular practice of meditation?
Meeting with Jesus did not result in a static experience for him. Nathaniel was promised that he would discover and enjoy many more things about Jesus. The promise by Jesus describes Nathaniel’s life on earth before he died, his life in heaven after he died, and his life in the glory to come after the resurrection. He now knows that Jesus keeps his promises. No doubt, his redeemed spirit is still meditating on what he discovers about his teacher, the divine Son who is the Messiah.