Sunan Ibn Majah
4290
Sahih+2

It was narrated from Ibn ‘Abbas that the Prophet (ﷺ) said:“We are the last of the nations, and the first to be brought to account. It will be said: ‘Where is the unlettered nation and its Prophet?’ So we are the last and the first.”

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi