Contradiction with 1 Samuel 29:4
This verse implies distrust in David's allegiance, while 1 Chronicles 12:7 speaks of warriors joining David, reflecting trust and support.
1 Samuel 29:4: And the princes of the Philistines were wroth with him; and the princes of the Philistines said unto him, Make this fellow return, that he may go again to his place which thou hast appointed him, and let him not go down with us to battle, lest in the battle he be an adversary to us: for wherewith should he reconcile himself unto his master? [should it] not [be] with the heads of these men?
Contradiction with 2 Samuel 3:1
Describes the long conflict between David's and Saul's houses, contrasting with the unity and support David receives in 1 Chronicles 12:7.
2 Samuel 3:1: Now there was long war between the house of Saul and the house of David: but David waxed stronger and stronger, and the house of Saul waxed weaker and weaker.