Musnad Abu Ya'la al-Mawsili 108:53

Abu Bakr narrated to us, Husayn ibn Ali narrated to us, from Za'idah, from Ibn Aqil, from Jabir, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Call out, O Umar, among the people that whoever dies worshipping Allah sincerely from his heart, Allah will admit him into Paradise and forbid the Fire upon him." He said: So Umar said, "O Messenger of Allah, shall I not give the people the good news?" He said, "No, lest they rely [upon it]."