Sunan an-Nasa'i, Book 44, Hadith 165 (In-Book) ⓘ
It was narrated that Hakim bin Hizam said: "I asked the Prophet "O Messenger of Allah, a man may come to me and ask me to sell him something that I do not have. Can I sell it to him then go and buy it from the market?' He said: 'Do not sell what you do not have.'''
حَدَّثَنَا زِيَادُ بْنُ أَيُّوبَ، قَالَ حَدَّثَنَا هُشَيْمٌ، قَالَ حَدَّثَنَا أَبُو بِشْرٍ، عَنْ يُوسُفَ بْنِ مَاهَكَ، عَنْ حَكِيمِ بْنِ حِزَامٍ، قَالَ سَأَلْتُ النَّبِيَّ صلى الله عليه وسلم فَقُلْتُ يَا رَسُولَ اللَّهِ يَأْتِينِي الرَّجُلُ فَيَسْأَلُنِي الْبَيْعَ لَيْسَ عِنْدِي أَبِيعُهُ مِنْهُ ثُمَّ أَبْتَاعُهُ لَهُ مِنَ السُّوقِ . قَالَ " لاَ تَبِعْ مَا لَيْسَ عِنْدَكَ " .
also referenced under: Hadith 4613 (Reference) & Volume 5, Book 44, Hadith 4617 (DarusSalam)