It is invalid to sell goods before taking possession of them
حَدَّثَنِي حَرْمَلَةُ بْنُ يَحْيَى، أَخْبَرَنَا عَبْدُ اللَّهِ بْنُ وَهْبٍ، حَدَّثَنِي عُمَرُ بْنُ مُحَمَّدٍ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " مَنِ اشْتَرَى طَعَامًا فَلاَ يَبِعْهُ حَتَّى يَسْتَوْفِيَهُ وَيَقْبِضَهُ " .
Ibn 'Umar (Allah be pleased with them) reported Allah's Messenger (ﷺ) as saying: He who bought foodgrain should not sell it until he had taken full possession of it (after measuring it).