Sunan Ibn Majah 1728

It was narrated from Abu Hurairah that the Messenger of Allah (ﷺ) said:“There are no days in this world during which worship is more beloved to Allah, Glorious is He, than the (first) ten days (of Dhul- Hijjah). Fasting one of these days is equivalent to fasting for one year, and one night of them is equal to Lailatul-Qadr.”