Sunan Abi Dawud — Commercial Transactions (Kitab Al-Buyu)

Ibn Rawahah assessed them (the amount of dates) at forty thousand wasqs, and when Ibn Rawahah gave them option, the Jews took the fruits in their possession and twenty thousand wasqs of dates were due from them.

“Whoever finds lost property, let him ask one or two men of good character to witness it, then he should not alter it nor conceal it. If its owner comes along, then he has more right to it, otherwise it belongs to Allah (SWT), Who gives it to whomsoever He wills.”