(23) باب الدُّعَاءِ
Narrated An-Nu'man ibn Bashir:
The Prophet (ﷺ) said: Supplication (du'a') is itself the worship. (He then recited:) "And your Lord said: Call on Me, I will answer you" (xI.60).
Reference: Sunan Abi Dawud 1479
In-book reference: Book 8, Hadith 64
English translation: Book 8, Hadith 1474