Authentic Supplication Number 220.

The Messenger of Allah  said: "The closest of the people to Allah are the ones that begin them with 'As-Salam [meaning the gathering]."

Reporters.
At-Tirmithi said it was comely, and Al-Albani said it was of sound ascription. Al-Albani included this hadeeth in The Authentic of Good Sayings as #157.