(a) It is narrated from Salih bin Abi Salih that he saw Abu Hurayrah (may Allah be pleased with him) leading the people in prayer, and he was reciting these words aloud: 'Rabbana inna na'udhu bika min al-shaytani al-rajim' (O our Lord, indeed we seek refuge with You from Satan the accursed). He recited this in the obligatory prayer after finishing Surah al-Fatihah.
(b) Imam al-Shafi'i (may Allah have mercy on him) said that Ibn Umar (may Allah be pleased with them both) used to recite the ta'awwudh within himself; so reciting it either aloud or quietly is correct. Some would recite the ta'awwudh even before Surah al-Fatihah, and this is my view.
(c) The Shaykh (may Allah have mercy on him) said that the narrations of the preceding chapter also indicate that the ta'awwudh is to be recited before the recitation.
(d) Imam al-Shafi'i (may Allah have mercy on him) said that the ta'awwudh is to be recited in the first rak'ah. The Shaykh (may Allah have mercy on him) said that this is also the view of al-Hasan, Ata and Ibrahim al-Nakha'i (may Allah have mercy on them).
(e) Another statement of Imam al-Shafi'i (may Allah have mercy on him) is that if the ta'awwudh is recited in every rak'ah before Surah al-Fatihah, it is good.
(f) The Shaykh (may Allah have mercy on him) said that it is reported from Ibn Sirin (may Allah have mercy on him) that he used to recite the ta'awwudh in every rak'ah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2359