صحیح ابن حبان
Ibn Hibban
كتاب الصوم
Book of Fasting
باب رؤية الهلال - ذكر البيان بأن قوله صلى الله عليه وسلم " فاقدروا له أراد به أعداد الثلاثين
Chapter on Sighting the Crescent - Clarifying that “estimate for it” means to complete thirty days
1 hadith
Hadith 3442
Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates: The Prophet Muhammad (peace and blessings be upon him) said: "Begin fasting upon seeing it (the new moon), and break your fast (celebrate Eid al-Fitr) upon seeing it. If clouds obscure it from you, then complete the count of thirty (days)."