Usul16

The Initiation of Salat, Its Prohibitions and Dissolution

faqih-67Vol. 1, p. 33

قَالَ أَمِيرُ الْمُؤْمِنِينَ عَلِيٌّ ع‌- افْتِتَاحُ الصَّلَاةِ الْوُضُوءُ وَ تَحْرِيمُهَا التَّكْبِيرُ وَ تَحْلِيلُهَا التَّسْلِيمُ.

Hadith.68 - The Commander of the Faithful Imam Ali ibn Abi Talib (as), said: "The initiation of prayer is purification (ablution), its prohibition is the takbir (saying 'Allahu Akbar'), and its permissibility is the Tasleem (saying 'Assalamu Alaikum')."