John Gill Commentary Joshua 7:12

"Therefore the children of Israel cannot stand before their enemies; they turn their backs before their enemies, because they are become accursed: I will not be with you any more, except ye destroy the devoted thing from among you." — Joshua 7:12 (ASV)

Therefore the children of Israel could not stand before their
enemies
Being forsaken of God for the sin committed among them:

[but] turned [their] backs before their enemies :
had not courage to face them, but fled as soon as they appeared:

because they were accursed ;
of God for the accursed thing that had been taken, as was threatened would be their case, should they take any of it; (Joshua 6:18) ;

neither will I be with you any more, until ye take away the accursed
thing from among you ;
that is, until they had put to death the person who had taken of the accursed thing, and made himself thereby accursed, and even all the camp of Israel; till this was done, the Lord would not be with them to protect and defend them, and give them success against their enemies.