Bukhari Collection: ::Book Number 5:: Hadith # 552
Narrated Ibn `Umar:Allah's Apostle appointed Usama bin Zaid as the commander of some people. Those people criticized his leadership. The Prophet said, "If you speak ill of his leadership, you have already spoken ill of his father's leadership before. By Allah, he deserved to be a Commander, and he was one of the most beloved persons to me and now this (i.e. Usama) is one of the most beloved persons to me after him.