The word which Isaiah the son of Amoz saw concerning Judah and Jerusalem.
It shall come to pass in the latter days that the mountain of the house of the LORD shall be established as the highest of the mountains, and shall be raised above the hills; and all the nations shall flow to it, and many peoples shall come, and say: "Come, let us go up to the mountain of the LORD, to the house of the God of Jacob; that he may teach us his ways and that we may walk in his paths." For out of Zion shall go forth the law, and the word of the LORD from Jerusalem. He shall judge between the nations, and shall decide for many peoples; and they shall beat their swords into plowshares, and their spears into pruning hooks; nation shall not lift up sword against nation, neither shall they learn war any more.
O house of Jacob, come, let us walk in the light of the LORD.
Hmmmm... That reading is used at Mass today, the short reading for Lauds is taken from it and it forms part of the scripture reading for the Office of Readings. Offhand, I can't think of any other piece of scripture that so dominates the liturgy on a particular day.