When the camp is to move, Aaron is to go in, and his sons, and they are to take down the curtain that is the screen and cover the ark of the Testimony with it, Bible see other translations

“his sons.” Aaron’s “sons” eventually were his descendants, who were the priests. Hebrew has no word for “grandson” or “grandfather.” There were just fathers and sons; ancestors and descendants.

“the curtain that is the screen.” The curtain that was the screen between the Holy Place and the Holy of Holies was used to cover the ark of the covenant when it was time to move the Tabernacle.

Commentary for: Numbers 4:5