Saul said to the Amalekite in
2 Samuel 1:9 'Stand here by me and kill me! I'm in the throes of death, but I'm still alive.'
Biblical Hermeneutics Stack Exchange is a question and answer site for professors, theologians, and those interested in exegetical analysis of biblical texts. It only takes a minute to sign up.Sign up to join this community
The Amalekite was lying - he was NOT at Saul's death and did not kill Saul. Saul killed himself as recorded in 1 Sam 31:1-6.
Following the battle, the escaped Amalekite was in a precarious situation and was technically an enemy of both sides of the battle and desperately needed a friend so he obviously fabricated a story to tell David in a desperate attempt to endear himself to David. He presumably reasoned that, "the enemy of my enemy is my friend"??
Whether David saw through this lie is not completely clear (I suspect as a prophet of God he may have?); however, David was angry with the Amalekite for killing the Lord's anointed, something that David had had the opportunity to do on several occasions but his personal ethics prevented him killing the "Lord's Anointed". 1 Sam 24, 26.
Thus, the Amalekite was not killed for obeying Saul's instruction (Saul's own armour bearer refrained from doing this, 1 Sam 31:4) because he had done nothing of the kind. The Amalekite was killed for say that he killed Saul, the Lord's anointed, 2 Sam 1:14-16.