The meaning of الخون (khawn) is deficiency, just as the meaning of الوفاء (wafa) is completeness. From it comes تخوّنه (takhawwanahu), if you diminish it. Then it was used in opposition to trustworthiness and fulfillment, because if you betray a man in something, you have introduced deficiency into it. It has also been borrowed to say: خان الدلو الكرب (khan al-dalu al-karb), and خان المشتار السبب (khan al-mushtaar al-sabab) because if it breaks, it is as if it has not fulfilled its purpose.

From it is His saying, وَتَخُونُوا أَماناتِكُمْ (and do not betray your trusts). The meaning is do not betray Allah by neglecting His obligations, and His Messenger by not following his example. And your أَماناتِكُمْ (trusts) among yourselves by not safeguarding them وَأَنْتُمْ تَعْلَمُونَ (while you know) the consequences and burdens of that. It is said, and you know that you are betraying, meaning that betrayal occurs from you intentionally, not by mistake. It is also said: and you are scholars who know the ugliness of evil and the goodness of good. It has been narrated that the Prophet of Allah, blessings and peace be upon him, besieged the Jews of Banu Qurayzah for twenty-one nights. They asked for peace just as their brothers Banu Nadir had done, to go to Aderaat and Ariha from the land of Sham. But the Messenger of Allah, blessings and peace be upon him, insisted that they submit to the judgment of Sa'd ibn Mu'adh. They refused and said: Send us Abu Lubabah ibn Abdul Mundhir, who was a well-wisher to them because his family and wealth were in their hands. He was sent to them and they asked him: What do you think, should we submit to the judgment of Sa'd? He gestured to his throat indicating slaughter. Abu Lubabah said: My feet did not move until I realized that I had betrayed Allah and His Messenger, so I descended and tied myself to a post of the mosque and said: By Allah, I will not taste food or drink until I die or Allah forgives me. He remained for seven days until he fell unconscious, then Allah forgave him. It was said to him: You have been forgiven, so untie yourself. He said: No, by Allah, I will not untie it until the Messenger of Allah, blessings and peace be upon him, unties me. He came to him and untied him with his hand and said: Indeed, part of my repentance is that I abandon the home of my people where I committed the sin, and that I renounce my wealth. The Messenger of Allah, blessings and peace be upon him, said: It is sufficient for you to give a third of it in charity. And regarding Al-Mughira: It was revealed concerning the killing of Uthman ibn Affan, may Allah be pleased with him. It is said that أَماناتِكُمْ (your trusts) refers to what Allah has entrusted you with of His obligations and limits. If you ask: Is وَتَخُونُوا (and do not betray) in the nominative or accusative? I say: It can be understood as a jussive included in the prohibition, or it can be accusative by implying 'that' as in وَتَكْتُمُوا الْحَقَّ (and conceal the truth). Mujahid read: وَتَخُونُوا أَمانتكم (and do not betray your trust) in the singular.