I wrote this a few years ago in order to find all of the scriptures in the Qur'an that justify non-defensive, religious based killing. The secondary purpose is to show that the Bible has verses which, viewed by a neutral observer, can be considered very brutal.
The conclusion I have come to, is that you can find reasons to demonize either Muslims or Christians. Both Muslims and Christians can and do find enough poorly interpreted verses in their own scriptures to justify brutality in the name of religion.
Qur'an
Defensive killing is justified
"Fight in God's cause against those who fight you, but do not overstep limits: God does not love those who overstep the limits. Kill them wherever you encounter them, and drive them out from where they drove you out, for persecution is more serious than killing. Do not fight them at the Sacred Mosque unless they fight you there. If they fight you, kill them -- this is what such disbelievers deserve -- but if they stop, then God is most forgiving and merciful. Fight them until there is no more persecution, and worship is devoted to God. If they cease hostilities, there can be no [further] hostility, except towards aggressors." (2:190-193)
No compulsion in religion
"Let there be no compulsion in religion. Truth stands out clear from Error; whoever rejects Evil and believes in God hath grasped the most trustworthy hand-hold, that never breaks. And God heareth and knoweth all things." (2:256)
Refrain from killing
"If thou dost stretch thy hand against me, to slay me, it is not for me to stretch my hand against thee to slay thee: for I do fear God, the Cherisher of the worlds" (5:28)
Cease fighting enemies who desire peace
"But if the enemy incline towards peace, do thou (also) incline towards peace, and trust in God: for He is the one that heareth and knoweth (all things)." (8:61)
Fighting prescribed for unbelievers who do not pay taxes. If they pay they are free to live their pagan ways in the Islamic state. All governments use force who do not pay taxes.
"Fight those who do not believe in God or in the Last Day and who do not consider unlawful what God and His Messenger have made unlawful and who do not adopt the religion of truth from those who were given the Scripture - [fight] until they give the jizyah willingly while they are humbled." (9:29)
Do not kill unbelievers, you cannot compel them to believe
"If it had been the Lord's Will they would all have believed all who are on earth! Wilt thou then compel mankind against their will to believe!" (10:99)
Peacemakers receive Eternal Life
"Those who patiently persevere, seeking the countenance their Lord; establish regular prayers; spend out of (the gifts) We have bestowed for their sustenance, secretly and openly; and turn off Evil with good: for such there is the final attainment of the (Eternal) Home" (13:22)
Let the un-believers alone to enjoy life
"Again and again will those who disbelieve wish that they had bowed (to God's Will) in Islam. Leave them alone, to enjoy (the good things of this life) and to please themselves: let (false) hope amuse them: soon will knowledge (undeceive them)." (15:2-3)
Messenger's only duty is to preach
"Obey God, and obey the Messenger: but if ye turn away, he is only responsible for the duty placed on him and ye for that placed on you. If ye obey him, ye shall be on right guidance. The Messenger's duty is only to preach the clear (Message)." (24:54)
Return good for evil
"Repel (Evil) with what is better: then will he between whom and thee was hatred become as it were thy friend and intimate!" (41:34)
Be good to those who do not fight you
"God does not forbid you from those who do not fight you because of religion and do not expel you from your homes - from being righteous toward them and acting justly toward them. Indeed, God loves those who act justly." (60:8)
To each his own
"O ye that reject Faith! I worship not that which ye worship, Nor will ye worship that which I worship. And I will not worship that which ye have been wont to worship, Nor will ye worship that which I worship. To you be your Way, and to me mine." (109)
In war, smite necks and fingers of aggressors
"I am with you. So make those who believe stand firm. I will throw fear into the hearts of those who disbelieve. Then smite the necks and smite of them each finger" (8:12)
See: Historical context
In war of reclaiming Mecca, slay idolaters after grace period is over.
"Then, when the sacred months have passed, slay the idolaters wherever ye find them, and take them (captive), and besiege them, and prepare for them each ambush. But if they repent and establish worship and pay the poor-due, then leave their way free. Lo! Allah is Forgiving, Merciful. And if anyone of the idolaters seeketh thy protection (O Muhammad), then protect him so that he may hear the Word of Allah, and afterward convey him to his place of safety. That is because they are a folk who know not." (9:5-6)
See: Quran says to kill them wherever you find them! Explanation by Nouman Ali Khan
Other
Various translations: Quran Explorer
Bible
I quote these verses without explanation and omit peaceful ones to show how the same standard applied to the Bible shows that it is much worse than the Qur'an.
Moses and Levites slaughter thousands who choose to worship another God.
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Mosaic Law warrants death for any number of minor offenses
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Kill unbelieving women and children
"Samaria shall become desolate; for she hath rebelled against her God: they shall fall by the sword: their infants shall be dashed in pieces, and their women with child shall be ripped up." (Hosea 13:16)
Kill those who don't follow the prophet
"And the man that will do presumptuously, and will not hearken unto the priest that standeth to minister there before the Lord thy God, or unto the judge, even that man shall die: and thou shalt put away the evil from Israel." (Deuteronomy 17:12)
Kill anyone of another religion
"He that sacrificeth unto any god, save unto the Lord only, he shall be utterly destroyed." (Exodus 20:22)
Kill unbelievers
"And they entered into a covenant to seek the Lord God of their fathers with all their heart and with all their soul; That whosoever would not seek the Lord God of Israel should be put to death, whether small or great, whether man or woman." (2 Chronicles 15:12-13)
Kill false prophets
"And it shall come to pass, that when any shall yet prophesy, then his father and his mother that begat him shall say unto him, Thou shalt not live; for thou speakest lies in the name of the Lord: and his father and his mother that begat him shall thrust him through when he prophesieth." (Zechariah 13:3)
Kill entire city if they worship another god
"Certain men, the children of Belial, are gone out from among you, and have withdrawn the inhabitants of their city, saying, Let us go and serve other gods, which ye have not known; Then shalt thou enquire, and make search, and ask diligently; and, behold, if it be truth, and the thing certain, that such abomination is wrought among you; Thou shalt surely smite the inhabitants of that city with the edge of the sword, destroying it utterly, and all that is therein, and the cattle thereof, with the edge of the sword. And thou shalt gather all the spoil of it into the midst of the street thereof, and shalt burn with fire the city, and all the spoil thereof every whit, for the Lord thy God: and it shall be an heap for ever; it shall not be built again." (Deuteronomy 13:13-16)
Saul commanded to kill all men, women, children and cattle of Amalekites because Amalek dared to go to war with them them 500 years earlier, even though Joshua slaughtered them.
"Thus saith the Lord of hosts, I remember that which Amalek did to Israel, how he laid wait for him in the way, when he came up from Egypt. Now go and smite Amalek, and utterly destroy all that they have, and spare them not; but slay both man and woman, infant and suckling, ox and sheep, camel and ass." (1 Samuel 15:2-3)
God is a god of war
"The Lord is a man of war: the Lord is his name." (Exodus 15:3)
Jesus doesn't want peace but war, even with infidels within the family.
"Think not that I am come to send peace on earth: I came not to send peace, but a sword. For I am come to set a man at variance against his father, and the daughter against her mother, and the daughter in law against her mother in law. And a man’s foes shall be they of his own household." (Matthew 10:34-36)