Sunan an-Nasa'i 3991
سنن النسائي#3991SahihIt was narrated that 'Abdullah said:"The Messenger of Allah [SAW] said: 'The first thing concerning which a person will be brought to account will be the Salah, and the first thing concerning which scores will be settled among the people, will be bloodshed
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
In-book reference: 37:26