Volume 3, Book 31, Number 179:
Narrated Ibn Abi Aufa:
I was with the Prophet on a journey, and he observed the fast till evening. The Prophet said to a
man, “Get down and mix Sawiq with water for me.” He replied, “Will you wait till it is evening?” The
Prophet said, “Get down and mix Sawiq with water for me; when you see night falling from this side,
the fasting person should break his fast.”