King David, a man after God's heart., was a man of “one thing” (Psalm 27:4). He set God as the top priority of his life. Around 1000 BC, as an outflow of his heart, he commanded that the Ark of the Covenant be brought up on the shoulders of the Levites amidst the sound of songs and musical instruments to his new capital city, Jerusalem. There he had it placed in a tent and appointed two hundred and eighty-eight prophetic singers and four thousand musicians to minister before the Lord, “to make petition, to give thanks and to praise the Lord” day and night (1 Chronicles 15:1–17:27).
This was unlike anything that had been done in Israel’s history, but it was God’s plan to release Heavenly worship on earth. King David's tabernacle was the first dedicated to 24/7 prayer and worship. Here are links to other Historical Witnesses of God's desire for 24/7 prayer and worship.