Exodus 25:16

And place inside the ark the Testimony, which I will give you.

Note The Testimony refers to the stone tablets in the ark of the covenant inscribed with the Ten Commandments; also in verses 21 and 22.

And thou shalt put into the ark the testimony which I shall give thee.

You shall put the covenant which I shall give you into the ark.

And thou shalt put into the ark the testimony which I shall give thee.