Contradiction with Exodus 14:14
The Lord shall fight for you, contradicting the idea of a physical battle between men as seen in 2 Samuel 2:17.
Exodus 14:14: The LORD shall fight for you, and ye shall hold your peace.
Contradiction with Matthew 5:9
Blessed are the peacemakers, contrasting with the violent encounter described in 2 Samuel 2:17.
Matthew 5:9: Blessed [are] the peacemakers: for they shall be called the children of God.
Contradiction with James 4:1
Describes wars and fighting as the result of lusts, which contradicts the battle in 2 Samuel 2:17 being depicted as a result of political conflict.
James 4:1: From whence [come] wars and fightings among you? [come they] not hence, [even] of your lusts that war in your members? [fightings: or, brawlings] [lusts: or, pleasures]
Contradiction with Romans 12:19
Advises against avenging oneself, whereas 2 Samuel 2:17 involves direct conflict and confrontation.
Romans 12:19: Dearly beloved, avenge not yourselves, but [rather] give place unto wrath: for it is written, Vengeance [is] mine; I will repay, saith the Lord.