Bukhari

Narrated Ibn 'Abbas (Radi-Allahu 'anhu):

The Prophet (Sallallahu 'Alaihi Wa Sallam) said, "If anyone of you, when
having sexual relation with his wife, say: 'In the name of Allah. O Allah!
Protect us from Satan and prevent Satan from approaching our offspring you
are going to give us,' and if he begets a child (as a result of that
relation) Satan will not harm it."

Bukhari Vol. 4 : No. 493

Narrated 'Abdullah (Radi-Allahu 'anhu):

It was mentioned before the Prophet (Sallallahu 'Alaihi Wa Sallam) that
there was a man who slept the night till morning (after sunrise). The
Prophet (Sallallahu 'Alaihi Wa Sallam) said, "He is a man in whose ears (or
ear) Satan had urinated."

Bukhari Vol. 4 : No. 492

Narrated Abu Huraira (Radi-Allahu 'anhu):

Allah's Apostle (Sallallahu 'Alaihi Wa Sallam) said, "During your sleep,
Satan knots three knots at the back of the head of each of you, and he
breathes the following words at each knot, 'The night is, long, so keep on
sleeping,' If that person wakes up and celebrates the praises of Allah,
then one knot is undone, and when he performs ablution the second knot is
undone, and when he prays, all the knots are undone, and he gets up in the
morning lively and gay, otherwise he gets up dull and gloomy."

Bukhari Vol. 4 : No. 491

As-Suyuti reported: The judge Abu Sa’eed responded comprehensively in regard to a question about the school of Ash-Shafi’ee with four rules (qawa’id); first, certainty does not remove doubt. The basis of this is the saying of the Prophet, peace and blessings be upon him, “Verily, Satan comes to one of you while he is in prayer and he says to him: you have lost your ablution; so do let him not leave unless he hears a sound or finds an odor.” Second, hardship leads to ease, and the basis of this is the saying of the Exalted, “We have not placed upon you hardship in religion,” (22:78) and the saying of the Prophet, “I was sent with the upright, lenient religion.” Third, harm should be removed, and the basis of this is the saying of the Prophet, “There is no harming, nor harming others.” Fourth, customs are a basis of judgment, because of the saying of the Prophet, “What the Muslims view as good is regarded by Allah as good.” Thus, he ended his letter. Other scholars said that these four rules are the pillars of jurisprudence (fiqh) and the entirety of doctrine, and some of them added to it a fifth rule, which is that matters are according to their objectives (maqasid), because of the saying of the Prophet, “Deeds are according to intentions,” and he said, “Islam is built upon five pillars,” and likewise jurisprudence is based upon five rules.

[As-Suyuti, Al-Ashbah wa Natha’ir 7-8]

قَالَ الْقَاضِي أَبُو سَعِيدٍ فَلَمَّا بَلَغَ الْقَاضِي حُسَيْنًا ذَلِكَ رَدَّ جَمِيع مَذْهَب الشَّافِعِيِّ إلَى أَرْبَع قَوَاعِد الْأُولَى الْيَقِين لَا يُزَال بِالشَّكِّ وَأَصْل ذَلِكَ قَوْله صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إنَّ الشَّيْطَانَ لَيَأْتِي أَحَدَكُمْ وَهُوَ فِي صَلَاته فَيَقُولُ لَهُ أَحْدَثْتَ فَلَا يَنْصَرِفْ حَتَّى يَسْمَعَ صَوْتًا أَوْ يَجِدَ رِيحًا وَالثَّانِيَة الْمَشَقَّة تَجْلِب التَّيْسِير قَالَ تَعَالَى وَمَا جَعَلَ عَلَيْكُمْ فِي الدِّينِ مِنْ حَرَجٍ وَقَالَ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بُعِثْتُ بِالْحَنِيفِيَّةِ السَّمْحَةِالثَّالِثَة الضَّرَر يُزَال وَأَصْلُهَا قَوْله صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ لَا ضَرَرَ وَلَا ضِرَارَ الرَّابِعَة الْعَادَة مُحَكَّمَةٌ لِقَوْلِهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَا رَآهُ الْمُسْلِمُونَ حَسَنًا فَهُوَ عِنْدَ اللَّهِ حَسَنٌ انْتَهَى قَالَ بَعْض الْمُتَأَخِّرِينَ فِي كَوْن هَذِهِ الْأَرْبَع دَعَائِم الْفِقْه كُلّه نَظَر فَإِنَّ غَالِبه لَا يَرْجِع إلَيْهَا إلَّا بِوَاسِطَةِ وَتَكَلُّف وَضَمّ بَعْض الْفُضَلَاء إلَى هَذِهِ قَاعِدَة خَامِسَة وَهِيَ الْأُمُور بِمَقَاصِدِهَا لِقَوْلِهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إنَّمَا الْأَعْمَالُ بِالنِّيَّاتِ وَقَالَ بُنِيَ الْإِسْلَامُ عَلَى خَمْسٍ وَالْفِقْه عَلَى خَمْس

7-8 الأشباه والنظائر السيوطي كتاب الأول في شرح القواعد الخمس التي ترجع إليها جميع مسائل الفقه