Abu al-Ḥusayn Ibn ʿAbd al-Raḥmān al-Malṭīyy (رحمه الله) (d. 337H) said:[1]
Chapter: Mention of the Murjiʾah.
I have mentioned the Murjiʾah in this book of ours at the beginning and end, since their saying is outside of what is common knowledge and reason.
Do you not see that amongst them is one who says: Whoever says 'There is none who has the right to be worshipped but Allāh and Muḥammad is His Messenger', and treats as unlawful what Allāh made unlawful and treats as lawful what Allāh made lawful, will enter Paradise when he dies, even if he fornicates, steals, kills, drinks alcohol and falsely accuses chaste women, abandons the prayer, zakāh and fasting so long as he affirms (the obligation of these actions), and he delays repentance. That his falling into major sins, his abandonment of the emphasized obligations and his commission of shameful deeds will not harm him.
And if he did any of that whilst declaring them lawful he is a disbeliever in Allāh, a polytheist and will exit from his faith and become from the inhabitants of the Fire, and that faith does not increase or decrease and that the faith of the Angels, Prophets, all the nations and the Scholars of the people and the ignorant ones is all one (and the same) [the faith of] none of them excels over [that of] another, fundamentally.
And he said at the end of the book:
And the Murjiʾah are twelve sects. A faction amongst them claimed that whoever bore witness with the testimonial of truth will enter Paradise no matter what his actions.
And just as no good deed will benefit alongside shirk, likewise, that alongside Tawḥid, no evil deed will harm (faith), and they claim that such a one will not enter the Fire at all, even if he commits the calamitous deeds (adhāʾim), abandons the obligations and commits the major sins.
The foundation of the innovation of the Murjiʾah is that perfect, complete faith can exist in the heart without any of the outward actions (see Ibn Taymiyyah). As such, all people, the most righteous and the most sinful, are equal in their faith. Also, that sins do not affect the faith that is in the heart, and that faith does not increase or decrease.