Anas bin Malik reported,

The Messenger of Allah ﷺ addressed the people and said, "Zayd took the banner and was struck down. Then Jafar took it and was struck down. Then Abdullah bin Rawaha took it and was struck down. Then Khalid bin Walid took it without having been appointed, and Allah granted victory through him."He then said, "It would not please me," or he said, "it would not please them, that they were here with us," while his eyes were overflowing with tears.

Bukhari 3063

Sahih

حدثنا يعقوب بن إبراهيم حدثنا ابن علية عن أيوب عن حميد بن هلال

عن أنس بن مالك رضي الله عنه قال

خطب رسول الله ﷺ فقال أخذ الراية زيد فأصيب ثم أخذها جعفر فأصيب ثم أخذها عبد الله بن رواحة فأصيب ثم أخذها خالد بن الوليد عن غير إمرة ففتح عليه وما يسرني أو قال ما يسرهم أنهم عندنا وقال وإن عينيه لتذرفان

البخاري 3063صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Bukhari
Book
Jihad and expeditions
Chapter
One who assumes command in war without prior authority when fearing the enemy
Numbering
Darussalam 3063
Bukhari 3063