Second Samuel 5 records David's capture of the Jebusite stronghold of Zion, which became the City of David. David established Jerusalem as his capital and subsequently brought the Ark of the Covenant into the city.
Zion became increasingly associated with God's presence, kingship, Temple, and covenant promises. The Psalms frequently celebrate Zion as God's chosen dwelling place and the city of the great King.
The prophets use Zion both geographically and symbolically. Zion may represent Jerusalem, its inhabitants, the covenant people, or the restored city anticipated in prophetic hope.
The New Testament continues this theological use. Hebrews contrasts earthly Sinai with Mount Zion and the heavenly Jerusalem, while Revelation depicts the Lamb standing on Mount Zion.