Verses with the word mischiefs in the Old Testament (3 verses):

Deuteronomy 32:23
I will heap mischiefs upon them; I will spend mine arrows upon them.

Psalms 52:2
The tongue deviseth mischiefs; like a sharp razor, working deceitfully.

Psalms 140:2
Which imagine mischiefs in their heart; continually are they gathered together for war.