Sahih Muslim 6923
صحيح مسلم#6923SahihIbn Abbas reported that Allah's Messenger (ﷺ) used to supplicate (with these words) and he (uttered these words) at the time of trouble; the rest of the hadith is the same except with this difference that insted of saying:" The Lord of heaven and the earth," he said:" The Lord of the heaven and that of the earth
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 48:115