2 Kings 6:22
“And he answered, Thou shalt not smite them: wouldest thou smite those whom thou hast taken captive with thy sword and with thy bow? set bread and water before them, that they may eat and drink, and go to their master.”
And it came to pass, when they were come into Samaria, that Elisha said, Lord, open the eyes of these men, that they may see. And the Lord opened their eyes, and they saw; and, behold, they were in the midst of Samaria.
And the king of Israel said unto Elisha, when he saw them, My father, shall I smite them? shall I smite them?
And he answered, Thou shalt not smite them: wouldest thou smite those whom thou hast taken captive with thy sword and with thy bow? set bread and water before them, that they may eat and drink, and go to their master.
And he prepared great provision for them: and when they had eaten and drunk, he sent them away, and they went to their master. So the bands of Syria came no more into the land of Israel.
And it came to pass after this, that Ben–hadad king of Syria gathered all his host, and went up, and besieged Samaria.
Counter-Arguments
The strongest case that this verse does not belong in this theme.

Cross-References
“But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you;”
“Therefore if thine enemy hunger, feed him; if he thirst, give him drink: for in so doing thou shalt heap coals of fire on his head.”
“If thine enemy be hungry, give him bread to eat; and if he be thirsty, give him water to drink:”
“For I will not trust in my bow, neither shall my sword save me.”
“Moreover I have given to thee one portion above thy brethren, which I took out of the hand of the Amorite with my sword and with my bow.”