Adam Clarke on Exodus 40:20

And put the testimony into the ark - That is, the two tables on which the ten commandments had been written. See Exo 25:16. The ark, the golden table with the shew-bread, the golden candlestick, and the golden altar of incense, were all in the tabernacle, within the veil or curtains, which served as a door, Exo 40:22, Exo 40:24, Exo 40:26. And the altar of burnt-offering was by the door, Exo 40:29. And the brazen laver, between the tent of the congregation and the brazen altar, Exo 40:30; still farther outward, that it might be the first thing the priests met with when entering into the court to minister, as their hands and feet must be washed before they could perform any part of the holy service, Exo 40:31, Exo 40:32. When all these things were thus placed, then the court that surrounded the tabernacle, which consisted of posts and hangings, was set up, Exo 40:33.