"I said to 'Umar : 'Allah said: That you shorten the Salat if you fear and the people are safe (4:101).' So 'Umar said: 'I wondered about that just as you have wondered. So I mentioned that to the Messenger of Allah (ﷺ), and he said: "It is charity which Allah has given to you, so accept His charity."
Jami` at-Tirmidhi Book 47, Hadith 86
← Previous Hadith "I saw Marwan bin Al-Hakam sitting in the Masjid, so I went over to him until I sat next to him. He informed us that Zaid bin Thabit informed him, that the Prophet (ﷺ) dictated: 'Not equal among the believers are those who sit and the Mujahidin in the cause of Allah.' He said: 'So Ibn Umm Maktum came and he was dictating to me that he said: "O Messenger of Allah! By Allah! If I were capable of Jihad then I would participate in Jihad.' And he was a blind a man. So Allah revealed to His Messenger (ﷺ) - while his thigh was against my thigh - and it became so heavy that I was worried it was about to fracture my thigh. Then he was relieved of it, so Allah had revealed to him: Except those who are disabled."

Jami` at-Tirmidhi Book 47, Hadith 85 Next Hadith → that the Messenger of Allah (ﷺ) halted between Dajnan and 'Usfan, and the idolaters aid: "These people have a prayer which is more loved to them than their fathers and their children." That is, 'Asr. They gathered their forces and advanced altogether. And Jibra'il came to the Prophet (ﷺ) and told him to divide his Companions into two lines and lead them in prayer, and another group stood behind them on guard with their weapons. Then the other group came and prayed one Rak'ah with him. Then these people stood guard with their weapons, so each of them performed one Rak'ah while the Messenger of Allah (ﷺ) performed two Rak'ahs.

Jami` at-Tirmidhi Book 47, Hadith 87