'It is Written' in the Bible

Our ancestors ate manna in the desert: as it is written, He gave them bread from heaven to eat."

In the prophets it is written, and they will be all instructed by God; everyone who has listened to the Father and learned from him, comes to me.

Why, it is written in your own Law that the evidence of two persons is valid:

And Jesus came across a young ass and seated himself on it; as it is written,