It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that when the people of Makkah drove the Prophet (peace and blessings be upon him) out, Sayyiduna Abu Bakr al-Siddiq (may Allah be pleased with him) said: "Inna lillahi wa inna ilayhi raji'un (We belong to Allah and to Him we return). They have driven out their Prophet (peace and blessings be upon him); now they will surely be destroyed." Ibn Abbas (may Allah be pleased with them both) said: Then this verse was revealed: "He has given permission to those who fight, because they have been wronged, and indeed Allah is fully able to help them." [Surah al-Hajj: 39] And Ibn Abbas (may Allah be pleased with them both) used to recite it as "adhina" (He has given permission). Sayyiduna Abu Bakr al-Siddiq (may Allah be pleased with him) said: "Then I knew that there would now be fighting." Ibn Abbas (may Allah be pleased with them both) said: This is the first verse revealed about fighting. This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), and they did not record it.

It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that Sayyiduna Abd al-Rahman bin Awf (may Allah be pleased with him) and some of his companions came to the Prophet (peace and blessings be upon him) and said: "O Prophet of Allah! When we were polytheists we enjoyed great honour and standing, but since we have believed we have become (outwardly) weak!" He (peace and blessings be upon him) said: "I have been commanded to pardon and forgive, so do not fight these people for now." Then, when Allah Almighty moved him (peace and blessings be upon him) to Madinah, he (peace and blessings be upon him) was commanded to fight, but they (some people) held back (from fighting). Then Allah, the Mighty and Majestic, revealed this verse: "Have you not seen those to whom it was said: Restrain your hands, establish the prayer and give the zakah? Then when fighting was prescribed for them, a group of them began to fear people (as Allah is feared)." [Surah al-Nisa: 77] This hadith is sahih (authentic) on the condition of Imam Bukhari, but the two Shaykhs did not record it.

It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both). Habib bin Shihab al-Anbari says: I heard my father say: I and a companion of ours came to Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both), and at his door we met Sayyiduna Abu Hurayrah (may Allah be pleased with him). He asked: "Who are you?" We told him, and he said: "Go to people who are over dates and water; indeed a valley flows only according to its capacity." We said: "May Allah reward you with good; seek permission for us to see Sayyiduna Ibn Abbas (may Allah be pleased with them both)." He sought permission for us, and then we heard Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrating from the Messenger of Allah (peace and blessings be upon him) that the Messenger of Allah (peace and blessings be upon him) delivered a sermon on the day of the Battle of Tabuk, and he (peace and blessings be upon him) said: "There is none among people better than a man who holds the reins of his horse, strives in the path of Allah and keeps himself away from the evils of people; and like a man who lives in the countryside with his flock, hosts his guest and fulfils his right." The narrator says: I asked: "Did he (peace and blessings be upon him) really say that?" He replied: "Yes, he (peace and blessings be upon him) said exactly that." I asked again: "Did he (peace and blessings be upon him) really say that?" He replied: "Yes, he (peace and blessings be upon him) said exactly that." He said this three times, so I proclaimed the greatness of Allah, praised Him and gave thanks. The chain of this hadith is sahih (authentic), but the two Shaykhs did not record it.

It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Shall I not tell you of the best of people in rank and station?" The Companions said: Certainly, O Messenger of Allah! He (peace and blessings be upon him) said: "A man who holds the reins of his horse in the path of Allah until he is martyred or death comes to him. Shall I not tell you of the one who comes next to him (in excellence)? A man who lives secluded (from habitation) in a mountain pass, establishes the prayer, gives the zakah and bears witness that there is no god but Allah." This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.

It is narrated from Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) that in the year of the Battle of Tabuk the Messenger of Allah (peace and blessings be upon him) addressed the people while leaning against the trunk of a date palm. He (peace and blessings be upon him) said: "Shall I not tell you of the best of people and the worst of people? Indeed, among the best of people is a man who worked in the path of Allah on the back of his horse, or on the back of his camel, or on his own feet, until death came to him. And among the worst of people is a sinful, reckless man who reads the Book of Allah but does not refrain from anything (of its warnings and commands)." This hadith has a sahih (authentic) chain, but the two Shaykhs did not record it.

It is narrated from Sayyiduna Uthman bin Affan (may Allah be pleased with him), while he was in Masjid al-Khayf at Mina, that he related that he heard the Messenger of Allah (peace and blessings be upon him) say: "One day (spent) in the path of Allah is better than a thousand days elsewhere." So let every person look to (provide good) for himself. This hadith is sahih (authentic) on the condition of Imam Bukhari, but the two Shaykhs did not record it.

It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that a man from among the Companions of the Prophet (peace and blessings be upon him) passed by a mountain pass in which there was a small spring of sweet water. Its purity and beauty pleased him greatly, and he said (to himself): If only I could withdraw from people and settle in this pass. Then he thought: I will certainly not do so until I seek permission from the Messenger of Allah (peace and blessings be upon him). So he mentioned it to the Messenger of Allah (peace and blessings be upon him), and he (peace and blessings be upon him) said: "Do not do that, for one of you standing (in the ranks) in the path of Allah is better than his praying among his family for sixty years. Do you not love that Allah should forgive you and admit you into Paradise? Fight in the path of Allah. Whoever fights in the path of Allah for as long as the interval between two milkings of a she-camel, Paradise becomes obligatory for him." This hadith is sahih (authentic) on the condition of Imam Muslim, but the two Shaykhs did not record it.

It is narrated from Sayyiduna Imran bin Husayn (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "A man's standing in the rank (on the battlefield) in the path of Allah is better in the sight of Allah than a man's worship of sixty years." This hadith is sahih (authentic) on the condition of Imam Bukhari, but the two Shaykhs did not record it.

It is narrated from Sayyiduna Abdullah bin Salam (may Allah be pleased with him): We, a group of the Companions of the Messenger of Allah (peace and blessings be upon him), were sitting, and we said to one another: "If only we knew which deed is most beloved to Allah Almighty, we would do it." Then Allah, the Mighty and Majestic, revealed this surah: "Whatever is in the heavens and whatever is on the earth glorifies Allah, and He is the All-Mighty, the All-Wise" [Surah al-Saff: 1] (to the end of the surah). The Messenger of Allah (peace and blessings be upon him) recited this whole surah to us in this way. Al-Awza'i said: Yahya bin Abi Kathir recited this surah to us in Makkah. Muhammad bin Kathir said: Al-Awza'i recited it to us in this way. Abu al-Walid said: Ibn Kathir recited it to us in this way. Abu al-Hasan bin Uqbah said: Abu al-Walid recited it to us in this way. Imam al-Hakim said: Shaykh Abu al-Hasan al-Shaybani recited it to us in this way. And Imam al-Hakim Abu Abdullah recited this surah to us from its beginning to its end. Al-Walid bin Muslim narrated it from al-Awza'i and made explicit the hearing (sama') from the beginning of the chain to its end.

It is narrated from Sayyiduna Abdullah bin Salam (may Allah be pleased with him): We were sitting with the Prophet (peace and blessings be upon him), and we said: "If only we knew which deed is most beloved to Allah Almighty." Then the narrator mentioned the whole account like the hadith above. This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it. My strongest opinion is that what led them to leave it is the narration of al-Hiql bin Ziyad, which differs from the narration of al-Walid bin Muslim and others.