The bedrock of Islamic thought is the Koran. This is supposed to be the word of God as conveyed to Muhammed. In addition to the Koran another source of Islamic thought is the Hadiths. These are supposed to be the words of Muhammed as heard by his followers. The Hadiths appeared about 200 years after the death of Muhammed. They are a collection of writings by renowned Islamic scholars and amplify and explain passages from the Koran.
The Koran states that a Muslim who has spent a lifetime in devotion to Allah and lived his life as per the tenets of Islam will on his death go to paradise, where his reward will be virgins of spotless beauty. The Koran does not specify any number. The Hadiths now come into the picture and specify that the true believer will be rewarded with 72 virgins and a number of boys in paradise.
The first 2 Hadiths are considered the most important and are referred to as the two Sahihs. Sham Imam Bukhari is the most famous of the compilers and he mentions that the Houris will not urinate, relieve nature, spit or have any nasal secretions. He goes on to say that their combs will be of gold and their sweat will smell like musk.
Islam has 2 main sects. They are the Sunni and Shia sects and both of them have different Hadiths, but the theme is generally the same. The specific Hadith in which the number of virgins is specified is Hadith Al-Tirmidhi in the Book of Sunah. This is in chapter 21 under the heading the Features of Paradise.
The Hadiths mention that the Prophet Muhammad was overheard saying the true believers deserve as a reward 80,000 servants and 72 wives. These wives and servants reside in a palace decorated with precious gems and the dome of this palace is wider than the distance from Al-Jabiyah (a Damascus suburb) to Sana’a (Capital of Modern Yemen).
Muslim theologians such as al Ghazali who died in 1111 AD and Al-Ash’ari who died in 935 AD have agreed that the virgins provide sensual pleasures in paradise. Al-Suyuti a famous Quranic commentator who died in 1505 AD also confirms this. The Hadiths lay stress on the fact that the women are spotless virgins. Ayah 74 states that no man or Jinn has ever touched them.
The Hadiths are an important pillar of Islam. Many Hadiths talk of sensual pleasures. According to Sahih Bukhari (volume I, Book 5, Page 268) mention is made of sexual strength of the almighty. The concept of the Houris in Koran is reinforced by the Hadiths.