It is recommended to be in a state of purity when remembering Allah, and that includes reciting the hadiths of the Messenger of Allah (blessings and peace of Allah be upon him). That was narrated from many of the early generations, and the soundest and most well-known example of that is narrated from Imam Malik (may Allah have mercy on him).

Supplications for entering the mosque include: “Allahumma iftah li abwaba rahmatika (O Allah, open to me the gates of Your mercy).” “ A`udhu Billah il-`Azim wa bi wajhihi’l-karim wa sultanihi’l-qadim min ash-shaytan ir-rajim (I seek refuge with Allah the Almighty and His noble countenance and His eternal power from the accursed Shaytan).” When exiting the mosque, one should say: “ Allahumma inni as’aluka min fadlika (O Allah, I ask You of Your bounty).” Regarding what the questioner said about it being recommended to say Amin when entering the mosque, there is no such report from the Prophet (blessings and peace of Allah be upon him) or from his Companions (may Allah be pleased with them), and we have not come across any of the scholars who said that.

The reason for writing down the hadiths was to protect them from being forgotten and disappearing, and also to make them available to the Muslims. The need to write them down became more important at the time of the junior Tabi‘in and those who came after them in the second century AH, when they began striving on a wider scale to seek out what the Sahabah had narrated of hadiths, along with their fatwas and verdicts; they also collected reports which contained the views of the Tabi‘in. When the chains of narration started to get longer and the isnads proliferated, and opinions that were contrary to the Sunnah began to spread and reports began to be fabricated, all of that motivated the scholars of hadith to select from the hadiths and reports that they had memorized what they thought was important to write down in books that would benefit the Muslims in general and students of hadith in particular.

All of the Muslim scholars accept ahaad hadiths concerning rulings on what is halaal and haraam. Most of them – and this is the view of Ahl as-Sunnah – also accept ahaad hadiths regarding beliefs. The issue of whether the reports are proven on the basis of probability or are definitive does not affect the obligation to accept them and act in accordance with them.