Exodus 25:16 Commentary: Rashi, Sforno, Rashbam & Siftei Chakhamim

ונתת אל הארן — It must be explained as though it were written בארון: [AND THOU SHALT PUT] INTO THE ARK,

ונתת אל הארון, the details were spelled out seeing this vessel had nothing to do with, and would not have been suitable for, sacrificial service.

את העדות, the Tablets which represented the testimony and covenant between G’d and Israel. This is also the reason why Moses refers to them as לוחות הברית, “Tablets of the covenant,” in Deuteronomy 9,9.