Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)

Bukhari :: Book 5 :: Volume 59 :: Hadith 744

Narrated Salim's father:

The Prophet appointed Usama as the commander of the troops (to be sent to Syria). The Muslims spoke about Usama (unfavorably ). The Prophet said, " I have been informed that you spoke about Usama. (Let it be known that ) he is the most beloved of all people to me."