John Gill Commentary Exodus 26:34

"And thou shalt put the mercy-seat upon the ark of the testimony in the most holy place." — Exodus 26:34 (ASV)

And you shall put the mercy seat upon ark of the testimony ,
&c.] With the cherubim of glory overshadowing it; all which were a representation of the way of man's salvation flowing from the mercy and grace of God, through the propitiation by Christ, and his perfect righteousness, by which the law is fulfilled; and all this is published in the Gospel by the ministers of it, signified by the cherubim: and these are all the things that were "in the most holy place"; and they were placed at the west end of it.