'It is Written' in the Bible

and they establish the thing, to cause to pass over an intimation into all Israel, from Beer-Sheba even unto Dan, to come in to make a passover to Jehovah, God of Israel, in Jerusalem, for not for a long time had they done as it is written.

for a multitude of the people, many from Ephraim and Manasseh, Issachar, and Zebulun, have not been cleansed, but have eaten the passover otherwise than it is written; but Hezekiah prayed for them, saying, 'Jehovah, who is good, doth receive atonement for every one

And a portion of the king, from his substance, is for burnt-offerings, for burnt-offerings of the morning, and of the evening, and the burnt-offerings of sabbaths, and of new moons, and of appointed seasons, as it is written in the law of Jehovah.

and they turn aside the burnt-offering, to put them by the divisions of the house of the fathers of the sons of the people, to bring near to Jehovah, as it is written in the book of Moses -- and so to the oxen.

And the rest of the matters of Josiah, and his kind acts, according as it is written in the law of Jehovah,