´‘Abdullah bin Buraidah narrated that his father said:` “The Messenger of Allah (ﷺ) said: ‘The covenant that distinguishes between us and them is prayer; so whoever leaves it, he has committed Kufr.’”
Hadith ReferenceSunan Ibn Majah / Establishing the Prayer and the Sunnah Regarding Them / Hadith: 1079
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:إسناده صحيح