Today is the feast of St. Bartholomew, so we have the Gospel of the call of ... Nathanael. (The slightly different lists of names of the Twelve Apostles led to the assumption that Bartholomew and Nathaniel are one and the same.) And the call of Nathanael is important for several reasons. In John's Gospel, Nathanael is the last of those called to follow Jesus at the very beginning of his ministry. And Nathanael's call involves a particular self-revelation on Jesus' part, when Jesus tells "him" (but speaks in the plural, so he's really broadcasting this to the group of disciples), "You will see heaven opened and the angels of God ascending and descending on the Son of Man."
That should have given all Twelve of them pause. Jesus was claiming to be, himself, personally, the ladder their ancestor Jacob had seen in a mysterious dream on his way out of the Promised Land. (Jacob had another mysterious experience on his way back to the Promised Land decades later.) Jacob could only dream about it; Jesus was saying that he himself was the pathway between heaven and earth. "No one comes to the Father except through me," he would later say at the Last Supper.
And it was Nathaniel who, in a certain sense, "evoked" this self-revelation from Jesus, preparing the way for it by his own exclamation of faith. Because Jesus didn't find Nathanael and say to him, "Come follow me." It was Philip who roused Nathanael (from under the fig tree?) and led him to Jesus, "the one about whom Moses wrote in the Law." When Jesus hinted to Nathanael that he not only knew him through and through, but saw him "under the fig tree," Nathanael simply said, "Rabbi, you are the Son of God; you are the King of Israel." In these words, John is offering us (at the beginning of the Gospel--this is Chapter 1) both a "Christology from above" and a "Christology from below"; a "descending" Christology coupled with an "ascending" one. As Son of God, Jesus is the One who "came down" to us; as "King of Israel" (and Jacob's new, God-given name was Israel), Jesus leads us to heaven.
Centuries later, Therese of Lisieux would update the ladder image by speaking of Jesus as an elevator (!); our Founder spoke of Jesus, Way, Truth and Life, as a car or vehicle. Whatever the image, Jesus sums up in himself all access, all communication, between God and humanity.