Volume 3, Book 34, Number 349:
Narrated ‘Abdullah bin ‘Umar:
Allah’s Apostle said, “Do not urge somebody to return what he has already bought (i.e. in optional sale) from another seller so as to sell him your own goods.”
Narrated Abu Said:
Allah’s Apostle forbade the selling by Munabadha, i.e. to sell one’s garment by casting it to the buyer not allowing him to examine or see it. Similarly he forbade the selling by Mulamasa. Mulamasa is to buy a garment, for example, by merely touching it, not looking at it.
Narrated Abu Huraira:
The Prophet said, “A time will come when one will not care how one gains one’s money, legally or illegally.”