Exodus 25:8, 21-22

And let them make Me a sanctuary, that I may dwell among them.

You shall put the mercy seat on top of the ark, and in the ark you shall put the Testimony that I will give you. And there I will meet with you, and I will speak with you from above the mercy seat, from between the two cherubim which are on the ark of the Testimony, about everything which I will give you in commandment to the children of Israel.