For some reason we are wired to think we have to contend with those who are considered to be our enemy alone, when God said vengeance belongs to him and through faith we too can stand as Moses did and say: Stand back and see the salvation of the Lord. For serving him gives liberty to our souls! (Romans 12:19-21) Dearly beloved, avenge not yourselves, but rather give place unto wrath: for it is written, Vengeance is mine; I will repay, saith the Lord.Therefore if thine enemy hunger, feed him; if he thirst, give him drink: for in so doing thou shalt heap coals of fire on his head. Be not overcome of evil, but overcome evil with good.(Exodus 14:13,14,21).
When we read of the blessings we receive by serving God we also see the curses brought to anyone that decides not to do the will of God. One of the many blessings his people receive is any enemy that rises up against us will we see smitten before our face as Gods protection is the best and only protection worth having in this life. (Deuteronomy 28:7). The Lord shall cause thine enemies that rise up against thee to be smitten before thy face: they shall come out against thee one way, and flee before thee seven ways.
As the Lords prayer tells us it is thy kingdom come, thy will be done which lets us know that it is Gods will and not our own that will be done and he will never leave us in the hands of anyone who rises up against us for this is our heritage from the hand of God! (Isaiah 54:14-17). In righteousness shalt thou be established: thou shalt be far from oppression; for thou shalt not fear: and from terror; for it shall not come near thee. Behold, they shall surely gather together, but not by me: whosoever shall gather together against thee shall fall for thy sake. Behold, I have created the smith that bloweth the coals in the fire, and that bringeth forth an instrument for his work; and I have created the waster to destroy. No weapon that is formed against thee shall prosper; and every tongue that shall rise against thee in judgment thou shalt condemn. This is the heritage of the servants of the Lord, and their righteousness is of me, saith the Lord.
David was well aware of false accusers that surrounded him at times, but gave the matter to the Lord as seen in Psalm 35.