At Bethel Jacob saw a stairway joining earth and heaven and called the place the house of God and gate of heaven.
Genesis 28:10-17 is the direct background; Daniel 7:13-14 also informs John's Son-of-Man language.
Jesus himself replaces the geographical holy place as the locus where heaven and earth meet.
This anticipates John's Temple and divine-presence themes: access to God is concentrated in Jesus.
Nathanael confesses Jesus as Son of God and King of Israel.