Sunan an-Nasa'i 855
سنن النسائي#855SahihIt was narrated from Abu Hurairah that the Messenger of Allah (ﷺ) said:"Whoever performs wudu' and does it well, then sets out for the Masjid and finds that the people have already prayed, Allah will decree for him a reward like that of those who attended (the prayer), without reducing the slightest from their reward
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiHasan
In-book reference: 10:79