The Messenger of Allah (peace and blessings be upon him) said: "Purification is half of faith." And the narrator mentioned the words 'al-hamdu lillah' (praise be to Allah) in place of 'Allahu akbar' (Allah is the Greatest), and 'al-salatu nur' (prayer is light) in place of 'al-sawmu junnah' (fasting is a shield).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 186