Hadith 8:1282
Abu Bakr narrated to us, he said: Muhammad ibn Fudayl narrated to us, from Yazid, from Mujahid, from Abdullah ibn Umar, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "There are no days in which deeds are more beloved to Allah than these days, the ten days. So increase in them the declaration of His greatness (Takbir), the declaration of His oneness (Tahlil), and the declaration of His praise (Tahmid)."
حدثنا أبو بكر قال حدثنا محمد بن فضيل عن يزيد عن مجاهد عن عبد الله بن عمر قال قال رسول الله صلى الله عليه وسلم ما من أيام أحب إلى الله فيهن العمل من هذه الأيام أيام العشر فاكثروا فيهن التكبير والتهليل والتحميد