Radak on Psalms
Break Thou the arm of the wicked: – Break his arm and his strength.
Rashi on Psalms
but as for the evil one—You will seek his wickedness and not find [it] As for the wicked of Israel, when they see the wicked [of the nations] prospering, their heart inspires them to deal wickedly, but when You break the arm of the wicked, if You were to come [then] to seek the wickedness of the wicked of Israel, You would not find it.