Exodus 16:34

As the Lord commanded Moses, so Aaron laid it up before the
testimony, to be kept.
] That is, before the ark of the testimony; when that was made, as it was in a little time after this, called the testimony, because it contained in it the law, which was a testimony or testification of the mind and will of God unto Israel, see ( Exodus 25:16 Exodus 25:21 Exodus 25:22 ) the apostle says, the pot of manna was in the ark, ( Hebrews 9:4 ) that is, on one side of it, (See Gill on Hebrews 9:4).