مختصر صحيح بخاري
Mukhtasar Sahih Bukhari
Book of Laylat al-Qadr
Seeking Laylat al-Qadr in the last ten odd nights.
It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Noble Prophet (peace and blessings be upon him) said: "Seek Laylat al-Qadr in the last ten nights of Ramadan when nine, seven, or five nights remain (that is, on the twenty-first, twenty-third, and twenty-fifth nights)."