'It is Written' in the Bible

and that they should publish and proclaim in all their cities, and in Jerusalem, saying, "Go out to the mountain, and get olive branches, and branches of wild olive, and myrtle branches, and palm branches, and branches of thick trees, to make booths, as it is written."

We cast lots, the priests, the Levites, and the people, for the wood offering, to bring it into the house of our God, according to our fathers' houses, at times appointed, year by year, to burn on the altar of the LORD our God, as it is written in the law;

also the firstborn of our sons, and of our livestock, as it is written in the law, and the firstborn of our herds and of our flocks, to bring to the house of our God, to the priests who minister in the house of our God;