Join none in worship with Allah. When a verse was revealed stating that those who believe should not mix their belief with wrong, companions of the Prophet wondered who among them had not mixed belief with wrong. Then Allah revealed a verse stating that joining others in worship with Allah is a great wrong indeed, and to join none in worship with Allah.

1. JOIN NONE IN WORSHIP WITH ALLAH

2.  Narrated 'Abdullah: When the Verse:-- 'Those who believe
and mix not their belief with wrong." was revealed, the
companions of the Prophet said, "Who amongst us has not
mixed his belief with wrong?" Then Allah revealed: "Join
none in worship with Allah, Verily joining others in worship
with Allah is a great wrong indeed."
(Sahih Al-Bukhari, Vol. 4, Hadith 638)