Why does it repeat "they carried it from Beis Avinadav"?
Radak #1: Now it explains how they carried it. Achyo was in front, and Uza was with the Aron.
Radak #2: Verse 3 teaches that they carried the Aron. Our verse discusses carrying the box [containing gold mice and Techorim that Pelishtim sent back with the Aron], and the Aron with it.
Malbim (3, 4): Verse 3 teaches that the wagon belonged to him. Our verse discusses carrying it from his house.
What was with the Aron?
Rashi: The verse is abbreviated; they were coming with the Aron.
Radak #1: They carried the wagon [mentioned at the end of verse 3] with the Aron.
Radak #2: Uza was with the Aron; Achyo was in front. Below (verse 7) it says that Uza died with the Aron.
Radak #3: The box that Pelishtim sent back with the Aron.
Malbim: "Im" teaches that they [carried it from the house, and] held the Aron itself with their hands. It must be carried via its staves! This is one of six ways in which they did not show proper honor for the Aron. 1
Malbim (3-5): The others are (a) They carried it on a wagon, and not on the shoulder. (b) They were conducting the wagon. Even the Pelishtim knew to let the cows lead it by themselves! (c) Uza and Achyo carried it, and not Leviyim. (d) Achyo was in front of the Aron; his backside faced it, which is disgraceful. The Pelishtim went in back of it! (e) David and Yisrael were jovial in a lightheaded way, not happy amidst fear, and did not play the special instruments for Avodah, and not via the Leviyim.
