مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3788
Musnad of Abdullah bin Mas'ood
‘Abdullah (رضي الله عنه) said: I heard the Messenger of Allah (ﷺ) say: “Whoever ascribes a rival to Allah, Allah will put him in Hell.” And he ('Abdullah) said: And there is something else I say that I did not hear from him: whoever dies not ascribing any rival to Allah, Allah will admit him to Paradise. And these prayers are expiation for whatever (sins) come in between, so long as killing (murder) is avoided.
Musnad Ahmad 3811Saheeh, this is a hasan isnad]