Contradiction with Matthew 5:44
Psalms 6:8 asks evildoers to depart, while Matthew 5:44 tells us to love and pray for our enemies.
Matthew 5:44: But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you;
Contradiction with Romans 12:14
Psalms 6:8 implies separation from wrongdoers, whereas Romans 12:14 encourages blessing those who persecute you.
Romans 12:14: Bless them which persecute you: bless, and curse not.
Contradiction with Proverbs 25:21-22
Psalms 6:8 rejects evildoers, whereas Proverbs 25:21-22 advises providing for your enemies' needs.
Proverbs 25:21-22: If thine enemy be hungry, give him bread to eat; and if he be thirsty, give him water to drink:
Contradiction with Luke 6:27-28
Psalms 6:8 seeks distance from evildoers, but Luke 6:27-28 advises loving and praying for those who mistreat you.
Luke 6:27-28: But I say unto you which hear, Love your enemies, do good to them which hate you,