'Ark of the Testimony' in the Bible

“When the camp prepares to move out, Aaron and his sons shall come into the sanctuary and take down the veil (curtain) screening off the Holy of Holies, and cover the ark of the testimony with it;

Now when Moses went into the Tent of Meeting (tabernacle) to speak with the Lord, he heard the voice speaking to him from above the mercy seat (the gold cover) that was on the ark of the Testimony from between the two cherubim; and He spoke [by special revelation] to him.