Hadith 4:245
Khalid ibn Makhlad narrated to us, from Ishaq ibn Hazim, he said: Abdullah ibn Abi Bakr ibn Amr ibn Hazm narrated to me, from Salim, from Ibn Umar, from Hafsa, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "There is no fasting for the one who does not establish it (i.e., make it obligatory) during the night."
حدثنا خالد بن مخلد عن إسحاق بن حازم قال حدثني عبد الله بن أبي بكر بن عمرو بن حزم عن سالم عن بن عمر عن حفصة قالت قال رسول الله صلى الله عليه وسلم لا صيام لمن لم يورضه ( ( ( يفرضه ) ) ) ( 1 ) بالليل