(183) باب مَنْ تَأَمَّرَ فِي الْحَرْبِ مِنْ غَيْرِ إِمْرَةٍ إِذَا خَافَ الْعَدُوَّ
Narrated Anas bin Malik:
Allah's Messenger (ﷺ) delivered a sermon and said, "Zaid received the flag and was martyred, then Ja`far took it and was martyred, then `Abdullah bin Rawaha took it and was martyred, and then Khalid bin Al-Walid took it without being appointed, and Allah gave him victory." The Prophet (ﷺ) added, "I am not pleased (or they will not be pleased) that they should remain (alive) with us," while his eyes were shedding tears.
Reference: Sahih al-Bukhari 3063
In-book reference: Book 56, Hadith 269
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 4, Book 52, Hadith 298