Musnad Ahmad 3737
Musnad of Abdullah bin Mas'ood
It was narrated that Ibn Mas'ood (رضي الله عنه) said: The Messenger of Allah (ﷺ) delayed 'Isha' prayer then he came out to the mosque and saw the people waiting for the prayer. He said: "Verily, none of the followers of these other religions is remembering Allah at this moment except you.” Then these verses were revealed: "Not all of them are alike; a party of the people of the Scripture stand for the right, they recite the Verses of Allah during the hours of the night, prostrating them- selves in prayer. They believe in Allah and the Last Day, they enjoin Al-Ma'roof (Islamic Monotheism, and following Prophet Muhammad (ﷺ)) and forbid Al-Munkar (polytheism, disbelief and opposing Prophet Muhammad (ﷺ)); and they hasten in (all) good works; and they are among the righteous. And whatever good they do, nothing will be rejected of them; for Allah knows well those who are Al-Muttaqoon (the pious" (Al ‘Imran 3.113-115).