John Gill Commentary Revelation 21:13

"on the east were three gates; and on the north three gates; and on the south three gates; and on the west three gates." — Revelation 21:13 (ASV)

On the east three gates
On which were written the names of Joseph, Benjamin, and Dan:

on the north three gates ;
on which were written the names of Reuben, Judah, and Levi:

on the south three gates ;
on which were written the names of Simeon, Issachar, and Zabulon:

and on the west three gates ;
on which were written the names of Gad, Asher, and Naphtali; see (Ezekiel 48:31–34) . This denotes the collection of the saints from all parts of the world, who shall come from east, west, north, and south, and sit down in the kingdom of God; and therefore here are gates at every point to enter in at; see (Isaiah 43:5Isaiah 43:6) (Luke 13:29) .