In 2 Samuel a man came to David claiming that he killed Saul in which David then killed the man because he admitted to killing the anointed one. Previously in 1 Samuel 31-4 when his armor bearer wouldn’t kill Saul, Saul killed himself by falling on his sword. Why the discrepancy?
Here we have another issue of a conflict within scripture. This is not uncommon nor does it give reason to discredit the bible. Often times there are good explanations for biblical discrepancy, sometimes it is impossible to know for sure. Some scholars may try to harmonize multiple accounts, i.e. they try to explain the problem in a way that makes both accounts work. This can be like trying to fit a square peg into a round hole.
In the case of Saul’s death, there have been attempts to harmonize the account that says Saul committed suicide, and the account in which the Amalekite says that he killed the King. Obviously, Saul could not have both committed suicide and been killed by the Amalekite.
I think that the explanation for the discrepancy can be as simple as saying that the Amalekite lied. This would not be much of a stretch considering that he brought the information to the (soon-to-be) king of Israel, David. The ruse may have been an attempt to gain favor from Saul’s arch nemesis David. Little did he know that David still bore great respect for Saul because he was God’s anointed king. The Amalekite must have been very surprised when David had him killed for saying that he murdered Israel’s king.
In the 2 Samuel 1 account, note also that it does not say what happened to Saul, it only tells us what the Amalekite said happened. This is different from the 1 Samuel 31 account in which the narrator simply spells out exactly what happened. If you read 2 Samuel 4:10 you will see that even David himself does not say that the Amalekite killed Saul. Rather, David says he killed the Amalekite because of what he said. Thus, it is much more likely that the account of Saul’s suicide in 1 Samuel 31 is the actual account of his death. Furthermore, there is really no disunity in the two accounts, since one of the accounts is likely a lie told by an enemy of Israel.