It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: Do not fast until you see the moon, and do not celebrate Eid until you see the moon. Rather, begin fasting upon sighting the moon, and celebrate Eid upon sighting the moon. If the moon is not visible and the sky is cloudy, then complete the count of thirty days.