It was narrated that Hakim bin Hizam said:
"I said: 'O Messenger of Allah, a man is asking me to sell him something that I do not possess; Shall I sell it to him?' He said: 'Do not sell what is not with you."' (DE)
English reference (DE): Vol. 3, Book 12, Hadith 2187 (DE)
Arabic reference (DE): Book 12, Hadith 2271 (DE)