Narrated ‘Abdullah bin Dinar:
One day Ibn ‘Umar, while in the Mosque, looked at a man who was dragging his clothes while walking in one of the corners of the Mosque He said, “See who is that. I wish he was near to me.” Somebody then said (to Ibn ‘Umar), “Don’t you know him, O Abu ‘Abdur-Rahman? He is Muhammad bin Usama.” On that Ibn ‘Umar bowed his head and dug the earth with his hands and then, said, “If Allah’s Apostle saw him, he would have loved him.”
Sahih Bukhari, Volume 5, Book57, Number 80