'It is Written' in the Bible

Jehoiada appointed the officers of the house of the LORD under the hand of the priests the Levites, whom David had distributed in the house of the LORD, to offer the burnt offerings of the LORD, as it is written in the law of Moses, with rejoicing and with singing, according to the order of David.

So they established a decree to make proclamation throughout all Israel, from Beersheba even to Dan, that they should come to keep the Passover to the LORD, the God of Israel, at Jerusalem: for they had not kept it in great numbers in such sort as it is written.

For a multitude of the people, even many of Ephraim and Manasseh, Issachar and Zebulun, had not cleansed themselves, yet they ate the Passover otherwise than it is written. For Hezekiah had prayed for them, saying, "May the good LORD pardon everyone

He appointed also the king's portion of his substance for the burnt offerings, for the morning and evening burnt offerings, and the burnt offerings for the Sabbaths, and for the new moons, and for the set feasts, as it is written in the law of the LORD.

They removed the burnt offerings, that they might give them according to the divisions of the fathers' houses of the children of the people, to offer to the LORD, as it is written in the book of Moses. So they did with the cattle.