Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "Listen! Paradise is not lawful for a disobedient one. Whoever meets Allah having broken his pledge of allegiance will meet Him with a severed hand. Whoever deliberately leaves the Jama'ah even by a hand-span has removed the noose of Islam from his neck. And whoever dies while owing no obedience to the Imam of the Jama'ah has died a death of Jahiliyyah."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17299