
Allah, The Most Exalted, says in His Holy book:“O you who believe! be careful of (your duty to) Allah with the care which is due to Him, and do not die unless you are Muslims.
And hold fast, all together, by the rope which Allah (stretches out for you), and be not divided among yourselves; and remember with gratitude Allah’s favour on you; for ye were enemies and He joined your hearts in love, so that by His Grace, ye became brethren; and ye were on the brink of the pit of Fire, and He saved you from it. Thus doth Allah make His Signs clear to you: That ye may be guided. Let there arise out of you a band of people inviting to all that is good, enjoining what is right, and forbidding what is wrong: They are the ones to attain felicity.
Be not like those who are divided amongst themselves and fall into disputations after receiving Clear Signs: For them is a dreadful penalty.”
(Ali-Imraan 3: 103-105)