Contradiction with Matthew 5:44
This verse instructs to love your enemies, which contrasts the gathering of forces for battle in 1 Chronicles 12:22.
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 12:19
This verse advises against taking revenge, which contradicts the military support gathered for David in 1 Chronicles 12:22.
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.
Contradiction with Proverbs 25:21-22
These verses suggest feeding your enemy if they are hungry, opposing the idea of assembling forces for a potential conflict as in 1 Chronicles 12:22.
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 Exodus 14:14
This verse states that the Lord will fight for you and you need only to be still, which conflicts with the action of gathering troops in 1 Chronicles 12:22.
Exodus 14:14: The LORD shall fight for you, and ye shall hold your peace.