The Muslim scholars are usually embarrassed by this question and pretend that it is not physical but a condition of the mind. The above Koranic verse clearly states that it is a definite exchange i.e. offer of paradise for killing a non- Muslim or getting killed in the process of obeying this divine command. The paradise is the main temptation for practising Islam. This is the reason that the Koran explains it well. Paradise is the description of the luxurious surroundings dwelt in by Houris and Ghilman.
Houris are the most beautiful ever-young virgins with wide, flexing eyes and swelling bosoms.
Ghilman are the immortal young boys, pretty like pearls, clothed in green silk and brocade an embellished with bracelets of silver. Allah shall give every believing man no fewer than seventy houris and many ghilmans. This is the ultimate goal of the Islamic morality, and it is why that the Muslims, who are usually depressed, are ready to practise convenient morality based on violence. Even more potent factor in this field is their staunch belief in the intercessory powers of the Prophet Muhammad, which means that he has the authority to accommodate his followers in paradise irrespective of what they may have done.