That we may know Jesus Christ and Believe - Studying the Gospels

These are written that you might believe that Jesus is the Christ, the what? Son of God. Right. And that believing ye might have life through his name.

Like the entire word, the Gospels contain no contradiction, error, or discrepancy. The chronology of the life of Jesus Christ is clearly discernible in the four Gospel accounts. That's the unity of the four Gospels.