It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Holy Prophet (peace and blessings be upon him) said: Do not fast one or two days before Ramadan, except for a person who has the habit of fasting, then he may fast. Begin fasting upon sighting the moon and celebrate Eid-ul-Fitr upon sighting the moon; if the sky is overcast, then complete thirty days of fasting.