What is the ruling on one who ate or drank in the daytime during Ramadan out of forgetfulness?

His fast is valid and there is no harm upon him, due to the Almighty's saying: (Our Lord, do not take us to task if we forget or make a mistake), and the Prophet's (peace be upon him) saying: "Whoever forgets while he is fasting and eats or drinks, let him complete his fast, for it was Allah who fed him and gave him drink." This includes intercourse and other things that break the fast when done out of forgetfulness.