Ayesha reported,
Saad was wounded on the day of the Trench. A man from Quraysh named Hibban bin Araqah shot him, striking him in the median vein of his arm. So the Prophet ﷺ pitched a tent for him in the mosque so he could visit him from nearby.When the Messenger of Allah ﷺ returned from the Trench, he laid down his weapons and bathed. Then Jibreel came to him, shaking the dust from his head, and said, "Have you laid down your weapons? By Allah, I have not laid mine down. Go out against them."The Prophet ﷺ asked, "Where to?"Jibreel pointed toward Banu Qurayzah. So the Messenger of Allah ﷺ went to them, and they surrendered to his judgment. He referred the judgment to Saad, who said, "I rule concerning them that the fighting men be killed, the women and children taken captive, and their property divided."Hisham reported that his father told him, on the authority of Ayesha, that Saad said, "O Allah, You know that there are no people I would rather fight in Your cause than those who denied Your Messenger ﷺ and drove him out. O Allah, I think You have ended the war between us and them. If anything remains of the war with Quraysh, then keep me alive for it so that I may fight them in Your cause. But if You have ended the war, then let this wound burst open and let my death be through it."His wound then burst open at the base of his throat. The first thing the people in a tent belonging to Banu Ghifar in the mosque noticed was blood flowing toward them. They said, "People of the tent, what is this coming to us from your direction?"There was Saad, his wound gushing blood, and he died from it 
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Azami 10215
Sahihعن عائشة قالت
أصيب سعد يوم الخندق، رماه رجل من قريش يقال له: حبان بن العرقة، رماه في الأكحل، فضرب النبي ﷺ خيمة في المسجد ليعوده من قريب، فلما رجع رسول الله ﷺ من الخندق وضع السلاح واغتسل، فأتاه جبريل عليه السلام وهو ينفض رأسه من الغبار، فقال: وضعت السلاح، والله ما وضعته، اخرج إليهم. قال النبي ﷺ: فأين؟ فأشار إلى بني قريظة، فأتاهم رسول الله ﷺ، فنزلوا على حكمه، فرد الحكم إلى سعد، قال: فإني أحكم فيهم: أن تقتل المقاتلة، وأن تسبى النساء والذرية، وأن تقسم أموالهم. قال هشام: فأخبرني أبي، عن عائشة، أن سعدا قال: اللهم إنك تعلم أنه ليس أحد أحب إلي أن أجاهدهم فيك من قوم كذبوا رسولك ﷺ وأخرجوه، اللهم فإني أظن أنك قد وضعت الحرب بيننا وبينهم، فإن كان بقي من حرب قريش شيء فأبقني له حتى أجاهدهم فيك، وإن كنت وضعت الحرب فافجرها، واجعل موتتي فيها. فانفجرت من لبته، فلم يرعهم وفي المسجد خيمة من بني غفار إلا الدم يسيل إليهم. فقالوا: يا أهل الخيمة، ما هذا الذي يأتينا من قبلكم؟ فإذا سعد يغذو جرحه دما، فمات منها رضي الله عنه.
Bukhari narrated it in the Book of Military Expeditions (4122), and Muslim narrated it in the Book of Jihad (1769-65), both through the route of Abdullah bin Numayr, who said, Hisham related to us, from his father, from Ayesha, and he mentioned it.It was also narrated from Mahmud bin Labeed, who said, when Saad's medial arm vein was struck on the day of the Trench and his condition became severe, they moved him to be near a woman called Rufayda, who used to treat the wounded. Whenever the Prophet 
passed by him, he would ask, "How did you fare this evening?" And when morning came he would say, "How did you fare this morning?" And Saad would inform him, until the night came when his people moved him, and his condition grew severe, so they carried him to Banu Abdul-Ashhal, to their dwellings.The Messenger of Allah ﷺ came, as he used to ask about him, and they said, they have already taken him away. So the Messenger of Allah ﷺ set out, and we went out with him, and he walked quickly until the straps of our sandals broke and our cloaks fell from our shoulders. His companions complained about this to him, saying, "O Messenger of Allah, you have tired us out with this walking." He said, "I fear that the angels will reach him before us and wash him as they washed Hanzala."The Messenger of Allah ﷺ reached the house while Saad was being washed, and his mother was weeping over him, saying,Woe to Umm Saad, Saad,
resolute and steadfast in grief.The Messenger of Allah ﷺ said, "Every wailing woman is lying except the mother of Saad."Then he was carried out. Mahmud said, the people, or those of them whom Allah willed, said to him, "O Messenger of Allah, we have never carried a dead man lighter for us than Saad." He said, "What should prevent him from being light for you, when such and such a number of angels have descended, who had never descended before this day of his? They have carried him along with you."Ibn Saad narrated it in Tabaqat (3/427-428) from Fadl bin Dukayn, who said, Abdul-Rahman bin Sulayman bin Ghasil informed us, from Asim bin Umar bin Qatada, from Mahmud bin Labeed, and he mentioned it.Abdul-Rahman bin Sulayman bin Ghasil's hadith is hasan when he does not contradict others. Ibn Hibban said, "He was among those who erred and made mistakes frequently, though he was truthful. What I lean toward is disregarding whatever reports of his contradict the trustworthy narrators, and citing as evidence whatever of his narrations agree with the trustworthy narrators."I say, and this is among what contradicts the reliable, trustworthy narrators, for they did not mention what he mentioned in the account of the death of Saad bin Muaz , his mother's wailing, and the Prophet's ﷺ confirmation of it.