Sunan an-Nasa'i 856
سنن النسائي#856SahihIt was narrated that 'Uthman bin 'Affan said:"I heard the Messenger of Allah (ﷺ) say: 'Whoever does wudu' properly, then walks to (attend) the prescribed prayer, and prays with the people or with the congregation or in the Masjid, Allah will forgive him his sins
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 ZaiSahih Muslim
In-book reference: 10:80