OK, just point out the verse where the Quran talks about Muslims being merciful to unbelievers "due to the mercy of GOD":
But if they repent, and perform the prayers, and pay the alms, then let them go their way. God is Most Forgiving, Most Merciful.
6. And if anyone of the polytheists asks you for protection, give him protection so that he may hear the Word of God; then escort him to his place of safety. That is because they are a people who do not know.
7. How can there be a treaty with the polytheists on the part of God and His Messenger, except for those with whom you made a treaty at the Sacred Mosque? As long as they are upright with you, be upright with them. God loves the pious.
8. How? Whenever they overcome you, they respect neither kinship nor treaty with you. They satisfy you with lip service, but their hearts refuse, and most of them are immoral.
9. They traded away God's revelations for a cheap price, so they barred others from His path. How evil is what they did.
10. Towards a believer they respect neither kinship nor treaty. These are the transgressors.
11. But if they repent, and perform the prayers, and give the obligatory charity, then they are your brethren in faith. We detail the revelations for a people who know.
14. Fight them. God will punish them at your hands, and humiliate them, and help you against them, and heal the hearts of a believing people.
15. And He will remove the anger of their hearts. God redeems whomever He wills. God is Knowledgeable and Wise.
16. Or do you think that you will be left alone, without God identifying which of you will strive, and take no supporters apart from God, His Messenger, and the believers? God is well Aware of what you do.
21. Their Lord announces to them good news of mercy from Him, and acceptance, and gardens wherein they will have lasting bliss.
22. Abiding therein forever. With God is a great reward.
23. O you who believe! Do not ally yourselves with your parents and your siblings if they prefer disbelief to belief. Whoever of you allies himself with them—these are the wrongdoers.
24. Say, “If your parents, and your children, and your siblings, and your spouses, and your relatives, and the wealth you have acquired, and a business you worry about, and homes you love, are more dear to you than God, and His Messenger, and the struggle in His cause, then wait until God executes His judgment.” God does not guide the sinful people.
25. God has given you victory in numerous regions; but on the day of Hunayn, your great number impressed you, but it availed you nothing; and the land, as spacious as it was, narrowed for you; and you turned your backs in retreat.
26. Then God sent down His serenity upon His Messenger, and upon the believers; and He sent down troops you did not see; and He punished those who disbelieved. Such is the recompense of the disbelievers.
27. Then, after that, God will relent towards whomever He wills. God is Forgiving and Merciful.
And fight the polytheists collectively, as they fight you collectively, and know that God is with the righteous.
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