A corrupt creed makes a person’s blood forfeit and renders his property lawful to seize. Allah the Exalted says: “Fight them until there is no more persecution and religion belongs entirely to Allah.” ⦗1⦘ And He says: “When the sacred months have passed, then kill the polytheists wherever you find them, capture them, besiege them, and lie in wait for them at every ambush point.” ⦗2⦘

Conversely, a sound creed yields wholesome effects on hearts, social conduct, and the very fabric of civilization. In the Prophet’s lifetime ﷺ two groups each built a mosque: one erected its mosque with righteous intention and pure devotion to Allah, while the other built its mosque for an evil purpose on the basis of a corrupt creed. Allah therefore commanded His Prophet to pray in the mosque founded upon piety, and He forbade him from praying in the mosque founded upon disbelief and malicious aims. Allah the Exalted says:

“Those who took a mosque for causing harm, fostering disbelief, dividing the believers, and as an outpost for those who had previously fought Allah and His Messenger will surely swear, ‘We intended nothing but good,’ yet Allah bears witness that they are liars. Never stand in it. A mosque founded upon piety from the first day is worthier for you to stand in. In it are men who love to purify themselves, and Allah loves those who purify themselves. Is he who laid the foundation of his building upon piety toward Allah and His pleasure better, or he who laid the foundation of his building upon the edge of a crumbling cliff so that it collapsed with him into the Fire of Hell? Allah does not guide the wrongdoing people.” ⦗3⦘