‘Amr b. al-Hamiq told that he heard God's Messenger say, “He who grants a man security and then kills him will be given the banner of treachery on the day of resurrection.”
There was a covenant between Mu'awiya and the Byzantines, and he was going towards their country; then when the covenant came to an end he attacked them. A man came on a horse, or a packhorse, saying, “God is most great, God is most great; let there be faithfulness and not treachery.”* And when they looked they found that he was 'Amr b. ‘Abasa. Mu'awiya questioned him about that and he replied that he had heard God’s Messenger say, "When one has a covenant with people he must not loosen or strengthen it till its term comes, or he brings it to an end in agreement with them.” He said that Mu'awiya then took the people back.
*Mirqat, 4, 255 says that 'Amr b. ‘Abasa felt it was an act of treachery to make a treaty while in one’s own country and then approach the enemy’s country when the period of the treaty was near an end, so as to be able to make an immediate attack.
I went to God’s Messenger in the year of the Conquest and found him bathing while his daughter Fatima was screening him with a garment. I gave a salutation and he asked who was there, then when I told him I was Umm Hani’ daughter of Abu Talib he said, “Welcome, Umm Hani’.” After he finished his bathing he got up and prayed eight rak'as wrapped in a garment, and when he was done I said, “Messenger of God, my mother’s son ‘Ali has asserted that he is going to kill a man to whom I have given protection, so and so the son of Hubaira.” He replied, “We have given protection to those to whom you have granted it, Umm Hani'.” She said that that was in the forenoon.
(Bukhari and Muslim.) In a version by Tirmidhi she said, “I have given protection to two of my husband’s male relatives,” and God’s Messenger replied, “We have given security to those to whom you have given it.”
