Psalms 59:5 - Matthew Poole's English Annotations on the Holy Bible

The God of Israel; a God in covenant with all true Israelites, whom thou hast promised to protect and bless. The heathen; or, these heathens, or Gentiles; who though they are called and accounted Israelites by their birth, yet in truth, and in their dispositions and manners, are mere heathens and barbarians; in which respect such men are elsewhere called strangers, Psalms 54:3, men of Sodom and Gomorrah, Isaiah 1:10, and as Ethiopians, Amos 9:7; as among us ungodly Christians are oft called Jews, or Turks or heathens. Be not merciful; for indeed thou canst not with thine honour, nor according to thy word, be merciful to any such incorrigible offenders. Wicked transgressors; or, perfidious transgressors; such as persecute me, and other good men, out of malice, and against their own consciences, which tell them that I am innocent, and with pretences of friendship. He might well pray so vehemently against such, not only for his own preservation, but for the just and necessary vindication of God's honour, and for the public good of mankind, whose common interest it was that such vile miscreants should be taken out of the way.