Exodus 26:34 in the King James Version
And thou shalt put the mercy seat upon the ark of the testimony in the most holy place.
Context
33 You shall hang up the veil under the clasps, and shall bring the ark of the covenant in there within the veil. The veil shall separate the holy place from the most holy for you.
34 You shall put the mercy seat on the ark of the covenant in the most holy place.
35 You shall set the table outside the veil, and the lamp stand opposite the table on the side of the tabernacle toward the south. You shall put the table on the north side.