Musannaf Ibn Abi Shayba 13:541

Abu Bakr narrated to us, he said: Yahya bin Zakariyya narrated to us, from Hajjaj, from al-Hakam, from Abu Razin, he said: I said to Masruq: "A man comes to me seeking ghee from me, and I do not have it. Should I buy it, then sell it to him?" He said: "No. But buy it and take possession of it at your place, then when he comes to you, sell it to him."