en_tn/num/32/13.md

Yahweh's anger was kindled against Israel

Yahweh becoming angry is spoken of as if his anger was a fire that begins to burn. This can be stated in active form. Alternate translation: "Yahweh became very angry with Israel" (See: rc://en/ta/man/translate/figs-metaphor and rc://en/ta/man/translate/figs-activepassive)

forty years

"40 years" (See: rc://en/ta/man/translate/translate-numbers)

all the generation ... sight was destroyed

This can be stated in active form. Alternate translation: "he destroyed all the generation ... sight" or "all the generation ... sight had died" (See: rc://en/ta/man/translate/figs-activepassive)

who had done evil in his sight

Being in someone's sight means to be in front of that person where he can see. Alternate translation: "who had done evil before Yahweh" or "who had done evil in Yahweh's presence" (See: rc://en/ta/man/translate/figs-idiom)