Sahih Muslim 1692
صحيح مسلم#1692SahihIbn 'Abbas reported that the Messenger of Allah (ﷺ) used to recite in the two (supererogatory) rak'ahs of the dawn prayer:" Say: We believed in Allah and what was revealed to us" and that which is found in Surah Al-i-'lmran:" Come to that word (creed) which is common between you and us" (iii)
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: 6:122