Musnad Ahmad 1018:78

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from Abu Ishaq, from Jurayy al-Nahdi, from a man from Banu Sulaym, that the Prophet, peace and blessings of Allah be upon him, counted [the phrases] on his hand, or on the hand of the Sulami, and said: "Subhan Allah (Glory be to Allah) is half of the Scale, and Al-Hamdulillah (Praise be to Allah) fills the Scale, and Allahu Akbar (Allah is the Greatest) fills what is between the heaven and the earth. And purification is half of faith, and fasting is half of patience."