Rabi` al-Awwal 22, 1330
1) You have, may Allah Almighty protect you, admitted that they lagged behind Usamah's regiment and were at Jurf reluctant to proceed in spite of being ordered by the Prophet (pbuh) to rush and expedite. You also admit that they did, indeed, raise questions about the [Prophet's] wisdom in appointing Usamah in spite of what they had seen and heard of deeds and words regarding his appointment.
You have further admitted that they did, indeed, request Abu Bakr to depose him even after seeing how angry the Prophet (pbuh) was when he noticed their questioning his appointment, his going out to them, feverish, bandaged, wrapped in a blanket, to deliver a sermon from the pulpit in which he repudiated their grumbling, a sermon you yourself have described as one of the significant historical events, one wherein he described Usamah as being worthy of such a post.
You have accepted the fact that they requested the caliph to cancel the regiment dispatched by the Messenger of Allah (pbuh), and untie the knot he, with his own eminent hands, had tied, in spite of seeing his concern about dispatching it and his complete care about expediting it, in addition to several statements he made regarding the necessity of doing so.
You have, moreover, admitted that some of those who had been drafted in that army by the Prophet (pbuh) himself who ordered them to enlist under Usamah's leadership had lagged behind. You have admitted all these facts which are written down in the books of history and are matters of consensus among the traditionists and historians, saying that they were not to be blamed for all what they had done. The summary of their pretext, as you have put it, is that they had preferred in those matters the interest of Islam according to their own views, not according to the Prophet's statements in their regard. We did not intend in this matter to state anything more than that. In other words, the topic of our discussion is whether they used to follow all the Prophet's statements or not. You have chosen the first, while we have chosen the second, and now your admission that they did not follow such statements proves our own viewpoint. Their being excused or not is obviously besides the point.
Since it has been proved according to your views that they preferred, in the incident of Usamah's regiment, the interest of Islam, following their own views rather than those of the Prophet as embedded in his statements, then why don't you likewise say that they preferred in the issue of caliphate to follow their own views regarding what is good for Islam to those of the Prophet (pbuh) as stated in his Ghadir hadith and the like? You have found excuses for those who cast doubts about Usamah's appointment, saying that they did so only because of his young age and their being middle-aged and old, and that old folks are naturally made to resent taking orders from the young; so, why don't you apply the same argument to those who did not follow the Ghadir texts appointing Ali (as), who was a young man, to take charge of middle-aged and elderly companions, who considered him young at the time when the Messenger of Allah, peace be upon him and his progeny, died just as they considered Usamah young when the Prophet (pbuh) appointed him as their commander in that regiment? What a big difference between caliphate and the leadership of a regiment! If their nature refused to accept the leadership of a youth in commanding one regiment, they were more liable to refuse the lifetime leadership of a youth in all religious and secular matters.
But your argument that middle-aged and elderly folks naturally resent receiving orders from the young is rejected if you apply it to all matters, since those whose faith is strong among elderly believers certainly do not resent being commanded by Allah and His Messenger to take orders from a youth, or in any other matter. "Nay! By thy Lord, they shall never truly believe till they totally accept your judgment in all their disputes, then they do not feel any hardship in accepting your judgment, submitting thereto wholeheartedly (Qur'an, 4:65)." "Whatever the Messenger grants you, take it, and abstain from whatever he forbids you (Qur'an, 59:7)."
2) As regarding al-Shahristani who discusses those who dodged the draft in Usamah's army, narrating their story as a generally accepted fact, it has been narrated in one hadith documented by Abu Bakr Ahmed ibn `Abdul-Aziz al-Jawhari in his book Al-Saqifa, from which I quote here this much for you verbatim:
"Ahmed ibn Ishaq ibn Salih has narrated a tradition to us from Ahmed ibn Siyar from Sa`d ibn Kathir al-Ansari whose men quote `Abdullah ibn `Abdul-Rahman saying that when the Messenger of Allah (pbuh) fell sick shortly before his death, he appointed Usamah ibn Zayd ibn Harithah to take charge in leading an army most of which were men from the Muhajirün and the Ansar. Among them were: Abu Bakr, `Umer, Abu `Ubaydah ibn al-Jarrah, `Abdul-Rahmn ibn `Awf, Talhah, and al-Zubayr, and ordered him to invade Mu'ta, where his father Zayd had been murdered, and to invade the valley of Palestine. Usamah slackened, and so did the rest of the army, and the Messenger of Allah, peace be upon him and his progeny, though sick, kept emphasizing that the army must rush there, till Usamah said to him: `O Messenger of Allah! Would you permit me to stay for a few days till Allah Almighty heals you?' He answered: `Go and proceed, supported by the blessings of Allah.' He said: `O Messenger of Allah! If I proceed while you are sick like that, I will be going with a heart swollen with pain.' He (pbuh) said: `Proceed towards victory in good health.' Usamah persisted: `But I hate to keep asking the travellers about your condition.' He said: `Proceed to carry out my orders,' then he, peace be upon him and his progeny, fainted. Usamah left and prepared to proceed. When the Messenger of Allah (pbuh) regained his consciousness, he immediately inquired about Usamah, and he was told that he and his men were preparing to proceed, whereupon he kept repeating: `Carry out Usamah's mission; the curse of Allah be upon whoever dodges its draft.' Usamah finally left the city, the flag above his head, surrounded by the companions, till he reached Jurf. In his company were Abu Bakr, `Umer, and most of the Muhajirün and the Ansar such as Asid ibn Hadr, Bashir ibn Sa`d, and many other dignitaries. Then he received a messenger sent by Umm Ayman who informed him to go ahead and enter the city because the Prophet (pbuh) was dying. He immediately left for Medina with the standard still in his hand. Having reached the Prophet's residence, he planted it at the door just when the Prophet (pbuh) had died."
This has been written down by a group of historians such as the Mu`tazilite scholar Ibn Abul-Hadid at the conclusion of page 20 and the succeeding page in Vol. 2 of his Sharh Nahjul Balaghah, Wassalam.