Imam Ahmad narrated from Ibn 'Umar (radhiAllaahu 'anhumaa) that
the Messenger of
Allah Muhammad (sallallaahu 'alaihi wa sallam) said, "There aren't any
days greater, nor
any days in which deeds done in them are more beloved to Allah Most
High, than these
ten days (of Dhul-Hijjah). So, increase saying Tahlil (Laailaaha
illallaah), and
Takbir (Allahuakkbar) and Tahmid (alhumdulillaah) in
them."
