Abu Hurairah (May Allah be pleased with him) reported:
The Messenger of Allah (sallallahu alayhi wasallam) said,
"On no days is the worship of Allah desired more than
in the first 10 days of Zil-Hijjah.
The fast of each of these days is equal to the fast of a whole year,
and the IBAADAT of each of these nights is equal to the
IBAADAT of LAILATUL QADR".
(Tirmizi & Ibn Maajah)