It is the most famous forties books that have emerged based on weak hadith says «Anyone save on my Omma forty hadiths from their
religion matters, sent by God Almighty the Day of Resurrection in the clique of scholars and scientists»
and An-Nawawi mentioned why he collected for those forty, and he said: «From scientists who collect forty in the fundamentals of Islam, and some of them in the branches, some of them in the jihad, and some of them in asceticism, some of them in hadiths, all the purposes of a valid, may Allah be pleased about the target»
and An-Nawawi has seen collect forty most important of all this, the forty hadiths containing all so, each hadith of them is an important principle of religion, and has been described by scientists as the Dar al-Islam upon,
or describes Islam or a third or so».