1 Kings 8:9

There was nothing in the ark, save the two tables of stone
which Moses put there at Horeb
That is, there were no other writings; or, as Ben Gersom says, no other part of the law, but the decalogue otherwise he observes there were in it Aaron's rod and the pot of manna, according to ( Hebrews 9:4 ) though the particle there may be rendered "at", or "with", or "by", (See Gill on Hebrews 9:4) and so they might be not within it, but in some place on the sides of it, see ( Deuteronomy 31:26 ) ,

when the Lord made a covenant with the children of Israel, when they
came out of the land of Egypt;
about two months after.