2 Samuel 1:10
So I stood upon him, and slew him, because I was sure that he could not live after that he was fallen: and I took the crown that was upon his head, and the bracelet that was on his arm, and have brought them hither unto my lord.
Cross-reference
2 Samuel 1:16
Parallel
2 Samuel 1:16 shows David using the Amalekite's own testimony from verse 10 to condemn him to death.
2 Samuel 12:30
Parallel
2 Samuel 12:30 describes David taking a king's crown, a parallel action to the Amalekite taking Saul's crown here.
1 Samuel 31:4
Contrast
1 Samuel 31:4 records Saul's suicide, directly contradicting the Amalekite's claim here that he killed Saul. This reveals the lie.
1 Samuel 31:5
Historical context
1 Samuel 31:5 shows the armourbearer saw Saul dead by suicide, further disproving the Amalekite's story.
1 Chronicles 10:4
Contrast
1 Chronicles 10:4 confirms Saul's suicide, contradicting the Amalekite's claim of killing him.
Judges 9:54
Parallel
Judges 9:54 has Abimelech asking his armor-bearer to kill him — mirrors the Amalekite's story of Saul's request.