It is reported that ʿAbdullāh b. Al-Mubārak said, “I once borrowed a pen in Al-Shām (Transjordan) and went to return it. But when I came back to Marwu (Eng. Merv , in Central Asia) I saw that I still had it, so I went back to Al-Shām to return it to its owner.”
Al-Dhahabī, Siyar A’lām Al-Nubalā`, Vol. 8 p395.