Exodus 26:34

Place the mercy seat on the Ark of the Covenant in the holy of holies.

Exodus 25:21

After you put into the ark the words of my covenant that I will give you, place the throne of mercy on top.

Exodus 40:20

He took the words of God's promise (covenant) and put them in the ark. He put the poles on the ark and placed the throne of mercy on top of the ark.

Hebrews 9:5

The cherubim of glory shadowing the mercy seat were above the Ark. Now is not the time to speak in detail.

Treasury of Scripture Knowledge

Summary

And thou shalt put the mercy seat upon the ark of the testimony in the most holy place.

General references

Bible References

Put the mercy seat

Exodus 25:21
After you put into the ark the words of my covenant that I will give you, place the throne of mercy on top.
Exodus 40:20
He took the words of God's promise (covenant) and put them in the ark. He put the poles on the ark and placed the throne of mercy on top of the ark.
Hebrews 9:5
The cherubim of glory shadowing the mercy seat were above the Ark. Now is not the time to speak in detail.

General references

Exodus 40:3
Place the Ark containing the words of my covenant inside it, and hang the canopy over the ark.
Mark 15:38
The veil of the temple was torn in two from the top to the bottom.