Where exactly does God hang out?
Sometimes it seems like God is wherever his worshipers are, but he does live in a specific place. Worship for God started off in the Tabernacle, which was essentially a big tent. Then, about three thousand years ago, Solomon, David's son, built a temple in Jerusalem—or Zion—that was literally God's home.
In Psalm 18, God listens to his people "from his temple" (18:6). And when the writer seeks guidance, he asks God, "O send out your light and your truth; let them lead me; let them bring me to your holy hill and your dwelling" (43:3). The temple lent Jerusalem a kind of aura: this was the place to be if you worshiped God. The whole "perfection of beauty" (50:2) thing didn't hurt either.
If you go to Jerusalem today, this language is everywhere, from government documents to city plaques. The Zionists took a ton of inspiration from these passages when they were first writing, and made sure it was part of the government's mandate when Israel took Jerusalem in 1967.