Went to Masjid, but found out congregational salah already finished..

It was narrated from Abu Hurayrah (may Allaah be pleased with him) that the Messenger of Allaah (صلىالله عليه وسلم) said:

“If a person does wudoo’ and does it well, then sets out for the mosque but finds that the people have already prayed, Allaah will decree for him a reward like that of those who prayed and were present, and that will not detract anything from their reward.”

Narrated by Abu Dawood (564), al-Nasaa’i (855); classed as saheeh by al-Albaani in Saheeh Abi Dawood.