Contradiction with 1 Samuel 15:2-3
These verses command the annihilation of the Amalekites, a stark contrast to David's alliance with them in 2 Samuel 3:22.
1 Samuel 15:2-3: Thus saith the LORD of hosts, I remember [that] which Amalek did to Israel, how he laid [wait] for him in the way, when he came up from Egypt.
Contradiction with 1 Kings 2:5
This verse recounts Joab's violence and bloodshed, contrasting with his initial peaceful return to Hebron in 2 Samuel 3:22.
1 Kings 2:5: Moreover thou knowest also what Joab the son of Zeruiah did to me, [and] what he did to the two captains of the hosts of Israel, unto Abner the son of Ner, and unto Amasa the son of Jether, whom he slew, and shed the blood of war in peace, and put the blood of war upon his girdle that [was] about his loins, and in his shoes that [were] on his feet. [shed: Heb. put]
Contradiction with 2 Samuel 2:18-23
Here, Joab's brother Asahel is killed by Abner, contradicting Joab's later unchallenged return in 2 Samuel 3:22.
2 Samuel 2:18-23: And there were three sons of Zeruiah there, Joab, and Abishai, and Asahel: and Asahel [was as] light of foot as a wild roe. [of foot: Heb. of his feet] [as a wild...: Heb. as one of the roes that is in the field]