Sahih Muslim 1575
صحيح مسلم#1575SahihIbn 'Abbas reported:Allah has prescribed the prayer through the word of your Prophet (ﷺ) as four rak'ahs when resident, two when travelling, and one when danger is present
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: 6:6