'It is Written' in the Bible

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

And we cast the lots among the priests, and the Levites, and the people, for the wood offering, to bring into the house of our God, according to the houses of our fathers, at times appointed year by year, to burn upon the altar of Jehovah our God, as it is written in the Law

and to bring the first-born of our sons, and of our cattle, as it is written in the Law, and the firstlings 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;