Exodus 25:21

25:21 You are to put the atonement lid on top of the ark, and in the ark you are to put the testimony I am giving you.

Exodus 40:20

40:20 He took the testimony and put it in the ark, attached the poles to the ark, and then put the atonement lid on the ark.

Hebrews 9:5

9:5 And above the ark ¹  were the cherubim ²  of glory overshadowing the mercy seat. Now is not the time to speak of these things in detail.

[9:5]  ¹ tn Grk “above it”; in the translation the referent (the ark) has been specified for clarity.

[9:5]  ² sn The cherubim (pl.) were an order of angels mentioned repeatedly in the OT but only here in the NT. They were associated with God’s presence, glory, and holiness. Their images that sat on top of the ark of the covenant are described in Exod 25:18-20.