Jeremiah 33:17-22King James Version (KJV)
17 For thus saith the Lord; David shall never want a man to sit upon the throne of the house of Israel;
18 Neither shall the priests the Levites want a man before me to offer burnt offerings, and to kindle meat offerings, and to do sacrifice continually.
19 And the word of the Lord came unto Jeremiah, saying,
20 Thus saith the Lord; If ye can break my covenant of the day, and my covenant of the night, and that there should not be day and night in their season;
21 Then may also my covenant be broken with David my servant, that he should not have a son to reign upon his throne; and with the Levites the priests, my ministers.
22 As the host of heaven cannot be numbered, neither the sand of the sea measured: so will I multiply the seed of David my servant, and the Levites that minister unto me.