Midrasch zu Tehillim 78:61

(Numb. 16:1:) NOW KORAH <BEN IZHAR BEN KOHATH BEN LEVI> BETOOK HIMSELF…. This text is related (to Prov. 18:19): A BROTHER OFFENDED IS MORE <FORMIDABLE> THAN A FORTIFIED CITY; <SUCH> CONTENTIONS ARE LIKE A CASTLE BAR. A BROTHER OFFENDED IS MORE <FORMIDABLE> THAN A FORTIFIED CITY. R. Aha said: this refers to Korah, who was one of the bearers of the Ark.²⁴Cf. above, Numb. 5a:2; Numb. R. 18:14. It is so stated (in Numb. 7:9) BUT TO THE CHILDREN OF KOHATH HE GAVE NO <WAGONS>, BECAUSE THEY HAD THE SERVICE OF THE HOLY OBJECTS, WHICH THEY CARRIED ON THEIR SHOULDERS. Now he was the greatest in the whole tribe, and yet he sinned against the Ark. (Prov. 18:19): A BROTHER OFFENDED IS MORE <FORMIDABLE> THAN A FORTIFIED CITY (literally: CITY OF STRENGTH <'oz>), and 'oz can only denote an Ark, as stated (in Ps. 78:61): AND HE HAS DELIVERED HIS STRENGTH ('oz) TO CAPTIVITY.²⁵The biblical context concerns the loss of the Ark from Shiloh.