Sayyiduna Abdullah bin Umar (may Allah be pleased with them) narrates: The Noble Prophet (peace and blessings be upon him) said: "Do not begin fasting until you see the crescent (of the new month), and do not celebrate Eid al-Fitr until you see it. However, if it is cloudy for you, then the ruling is different; if it is cloudy for you, then complete the counting (of the days)."