The Five Normative Legal Maxims

     al-Qadi Husayn mentioned that the Shafi'i school revolves around four main legal maxims:

1. al-Yaqin la yuzalu bish-shakk: certainty is not overruled by doubt. The basis of this axiom is the words of the Prophet (may Allah bless him and give him peace): " Verily, the devil comes while you are in prayer and says to you, "you nullified your ritual purity, you nullified your ritual purity." Such a person should continue praying unless a sound is heard or a smell is found (indicating that one's ritual purity is nullified)."
2. al-Mashaqqat tujlab al-taysir: hardship begets facility. The basis of this axiom is in the words of Allah: " And no hardship has been placed upon you in the religion," and the statement of the Prophet (may Allah bless him and give him peace): " I have been sent with an easy, accommodating religion." 
3. al-Darar muzal: harm must be eliminated. The basis for this maxim is the hadith of the Prophet (may Allah bless him and give him peace): "Harm may neither be inflicted nor reciprocated in Islam."
4. Tahkim al-'Adat wa al-ruju' ilayha: custom is the basis of judgement. This axiom is derived from the verse of Surat al-Nur: " O you who have believed, let those whom your right hands possess and those who have not [yet] reached puberty among you ask permission of you [before entering] at three times...," and the statement the Prophet (may Allah bless him and give) made to Hamnah bint Jahsh: " Observe your menses for six or seven days, Allah alone knows which it should be, just as other women, and purify just as other women purify at the time of their menstruation and purification."  

     Some other great scholars added a fifth legal maxim: al-Umur bi-maqasidiha: acts are judged by the intention behind them. This axiom is based on the hadith: " Acts are valued in accordance with their underlying intention." This is a fine addition to the existing four normative legal maxims, for al-Shafi'i said: " This hadith constitutes a third of all knowledge."

     Finally, Sultan al-'Ulama, 'Izz al-din bin 'Abd al-Salam, held that all matters of fiqh return to one single legal maxim: the attraction of benefit and the prevention of evil; however, other scholars felt that all matters of fiqh return to the acquisition of benefit alone ( al-Fawa'id al-Janiyyah 1/139-43).

Works Cited

al-Fadani, Muhammad Yasin. al-Fawa'id al-Janiyyah Hashiyat al-Mawahib al-Saniyyah. Lebanon; Dar--       

     al-Basha'ir al-Islamiyyah, 1996. Print.

al-Hisni, Taqi al-Din. Kitab al-Qawa'id. Riyadh, Saudi Arabia; Maktabat al-Rushd, 1997. Print.