Thus, faith in the Messenger and jihad in defence of his religion were a cause of good in this world and the Hereafter. Conversely, religious innovations, heresy, and opposition to what he brought are a cause of evil in this world and the Hereafter. When heresy and religious innovations spread in Syria, Egypt, and al-Jazīra, the unbelievers were given power over their people. But when they upheld Islam to the extent that they did and subdued the heretics and religious innovators, Allah granted them victory over the unbelievers, in fulfilment of His words:

“O you who believe, shall I direct you to a transaction that will save you from a painful punishment? Believe in Allah and His Messenger and strive in Allah’s cause with your wealth and your lives. That is better for you, if only you knew. He will forgive your sins and admit you into gardens beneath which rivers flow, and pleasant dwellings in Gardens of perpetual residence. That is the great triumph. And He will grant you something else that you love: help from Allah and an imminent victory. So give glad tidings to the believers.”

Likewise, when the people of the East upheld Islam, they were granted victory over the polytheistic unbelievers among the Turks, the Indians, the Chinese, and others. But when religious innovations, heresy, and wickedness spread among them as they did, the unbelievers were given power over them. The Most High said:

“We decreed for the Children of Israel in the Scripture: ‘You will surely spread corruption in the land twice, and you will surely become exceedingly arrogant.’ When the first promise came to pass, We sent against you servants of Ours endowed with great military might, and they swept through your homes. It was a promise fulfilled. Then We restored your ascendancy over them, supplied you with wealth and sons, and made you greater in numbers. If you do good, you do good for yourselves; and if you do evil, it is against yourselves. Then, when the latter promise came to pass