Albert Barnes Commentary Psalms 37:15

"Their sword shall enter into their own heart, And their bows shall be broken." — Psalms 37:15 (ASV)

Their sword shall enter into their own heart - Their purposes will recoil on themselves; or they will themselves suffer what they had devised for others. See the same sentiment expressed in Psalms 7:15-16; Psalms 9:15; compare Esther 7:10.

And their bows shall be broken - They will be defeated in their plans. God will cut them off, and not allow them to execute their designs.