They Found Out During The Day That Ramadan Had Begun, So They Fasted
The Awqaf -
Some of our Muslim brothers did not know that
Ramadaan had begun until after the sun had risen, but
they completed their fast. Is that sufficient or do
they have to repeat their fast?.
Praise be to Allaah.
They have done the right thing by refraining from
eating etc for the rest of the day, but they have to
fast another day in its stead.
Standing Committee for Academic Research and Issuing
The reason why they have to make up the fast is that
they did not have the intention of fasting from the
night before. The Prophet (peace and blessings of
Allaah be upon him) said: "Whoever does not make the
intention before dawn, there is no fast for him."
Narrated by Ahmad, 6/287; Abu Dawood, no. 2454; al-Tirmidhi,
730; al-Nasaa'i, 2331; classed as saheeh by al-Albaani
in Saheeh Abi Dawood, 2143.