Jami` at-Tirmidhi 3371
جامع الترمذي#3371Da'ifAnas bin Malik narrated that :the Prophet said: “The supplication is the essence of worship.”
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirDaif
Al-AlbaniDaif
Zubair Ali ZaiDaif
In-book reference: 48:2