Narrated Hakim b. Hizam:

"I asked Messenger of Allah ﷺ, I said: 'A man came to me asking to buy something that I did not have. Can I buy it from the market for him and then give it to him?' He said: 'Do not sell what is not with you.'"

He said: There are narrations on this topic from 'Abdullah bin 'Umar.

حَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا هُشَيْمٌ، عَنْ أَبِي بِشْرٍ، عَنْ يُوسُفَ بْنِ مَاهَكَ، عَنْ حَكِيمِ بْنِ حِزَامٍ، قَالَ أَتَيْتُ رَسُولَ اللَّهِ ﷺ فَقُلْتُ يَأْتِينِي الرَّجُلُ يَسْأَلُنِي مِنَ الْبَيْعِ مَا لَيْسَ عِنْدِي أَبْتَاعُ لَهُ مِنَ السُّوقِ ثُمَّ أَبِيعُهُ قَالَ " لاَ تَبِعْ مَا لَيْسَ عِنْدَكَ " . قَالَ وَفِي الْبَابِ عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ .