Burayda bin Husayb reported,

The Messenger of Allah ﷺ heard a man saying, "O Allah, I ask You by my testimony that You are Allah, there is no god but You, the One, the Eternal Refuge, who has not begotten and was not begotten, and to whom none is equal."The Messenger of Allah ﷺ said, "You have asked Allah by the name which, when He is asked by it, He gives, and when He is called upon by it, He answers."

Azami 11035

Sahih

عن بريدة بن الحصيب الأسلمي

أن رسول الله ﷺ سمع رجلا يقول: اللهم إني أسألك أني أشهد أنك أنت الله لا إله إلا أنت الأحد الصمد الذي لم يلد، ولم يولد، ولم يكن له كفوا أحد. فقال رسول الله ﷺ: لقد سألت الله بالاسم الذي إذا سئل به أعطى، وإذا دعى به أجاب.

الأعظمي 11035صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Supplications, remembrances, and prayer upon the chosen Prophet ﷺ
Chapter
Supplications of adhan and prayer, and what is related to them
Section
Supplications before the taslim
Numbering
Jami al-Kamil 11035 (2nd edition)
Azami 11035