Nathanael answered him, "Rabbi, you are the Son of God! You are King of Israel!"
The King of Israel - This was one of the titles by which the Messiah was expected, and this was the title which was affixed to his cross, John 19:18. This case of Nathanael John adduces as another evidence that Jesus was the Christ. The great object he had in view in writing this gospel was to collect the evidence that he was the Messiah, John 20:31. A case, therefore, where Jesus searched the heart, and where his knowledge of the heart convinced a pious Jew that he was the Christ, is very properly adduced as important testimony.