Nafi' thus reported on the authority of Ibn 'Umar (RA): We entered into the state of Ihram with Allah's Messenger (ﷺ) for Hajj Mufrad and in the narration of Ibn 'Aun (the words are): "Allah's Messenger (ﷺ) entered into the state of Ihram (with the intention) of Hajj Mufrad."
'A'isha reported Allah's Messenger (ﷺ) as saying: He who innovates things in our affairs for which there is no valid (reason) (commits sin) and these are to be rejected.
It has been narrated on the authority of Abu Hurairah (RA) that the Messenger of Allah (ﷺ) said: No two such persons shall be together in Hell as if one of them is such that his presence hurts the other. It was asked: Messenger of Allah, who are they? He said: A believer who killed a disbeliever and (then) kept to the right path."