The Cause of My Enemy Being My Enemy

Psalm 7:1-5

1  O LORD my God, in thee do I put my trust: save me from all them that persecute me, and deliver me: 
2  Lest he tear my soul like a lion, rending it in pieces, while there is none to deliver. 
3  O LORD my God, if I have done this; if there be iniquity in my hands; 
4  If I have rewarded evil unto him that was at peace with me; (yea, I have delivered him that without cause is mine enemy:) 
5  Let the enemy persecute my soul, and take it; yea, let him tread down my life upon the earth, and lay mine honour in the dust. Selah.