(1) باب إِبْطَالِ بَيْعِ الْمُلاَمَسَةِ وَالْمُنَابَذَةِ
Abu Huraira (Allah be pleased with him) reported:
Two types of trarisactions have been forbidden (by the Holy Prophet), al-Mlulamasa and al-Munabadha. As far as Mulamasa transaction is concerned, it is that every one of them (the parties entering into transaction) should touch the garment of the other without careful consideration, and al-Munabadha is that every one of them should throw his cloth to the other and one of them should not see the cloth of his friend.
Reference: Sahih Muslim 1511 e
In-book reference: Book 21, Hadith 5
USC-MSA web (English) reference(deprecated numbering scheme): Book 10, Hadith 3612