Ok, I will try to be a little more clear on the issue of Muslims and Christians having the same God, especially in light of Old Testament and Qur'anic commands to kill.
***Islam teaches that there is only One God, in the sense of One Creator worthy of our love and submission in obedience, but that there are also many gods in the sense of what or who people may chose to devote themselves to instead of or in addition to the One God. We also believe that the Jews who originally embraced the message of Prophet Jesus, peace be upon him, were monotheists and did not espouse the divinity of Jesus, nor did he present himself as God the Son or Son of God.
"Then see you such a one as takes as his god his own vain desire?" (Qur'an 45:23)
"Yet they have taken, besides Him, gods that can create nothing but are themselves created..." (Qur'an 25:3)
"Allah, there is no god but He--the Living, the Self-subsisting, Eternal." (Qur'an 2:255)
"To Allah belong the east and the West: Whithersoever ye turn, there is the presence of Allah. For Allah is all-Pervading, all-Knowing. They say: "Allah hath begotten a son": Glory be to Him.--Nay, to Him belongs all that is in the heavens and on earth: everything renders worship to Him. To Him is due the primal origin of the heavens and the earth: When He decreeth a matter, He saith to it: "Be," and it is." (Qur'an 2:115-117)
"The similitude of Jesus before Allah is as that of Adam; He created him from dust, then said to him: "Be". And he was." (Qur'an 3:59)
"They do blaspheme who say: Allah is one of three in a Trinity: for there is no God except One God." (Qur'an 5:73)
"Say you: 'We believe in Allah, and the revelation given to us, and to Abraham, Ishmael, Isaac, Jacob and that given to Moses and Jesus, and that given to (all) Prophets from their Lord..." (Qur'an 2:136)
"Say: Will ye dispute with us about Allah, seeing that He is our Lord and your Lord; that we are responsible for our doings and ye for yours; and that We are sincere (in our faith) in Him?" (Qur'an 2:139)
***Islam teaches that Muslims are to kill in war waged for self-defense and self-preservation. "Fight in the cause of Allah those who fight you..." (Qur'an 2:190)
"Jihad has been defined as being both a collective and an individual duty. Hence interpreters write that if Islam, or the Muslim community, is attacked, jihad is incumbent upon all Muslims and is required even of those who are normally noncombatants. Then, the nature of an attack, whether imminent and literal or the drawn out cultural onslaught of the West in tandem with specific political or military actions such as the war in Iraq, could alter the understanding of the jihad duty.
"However, the requirement to participate in a
jihad could be met in several ways: by waging war a) with the heart, b) with the tongue, c) with the hands, and d) with the sword. Jihad also means a personal struggle to live as a true Muslim. When jihad is considered a collective duty, there is no need to have a religious or political official proclaim it. However, from the standpoint of an individual duty and a just pursuit of war, this should occur."
http://www.strategicstudiesinstitute.army.mil/pdffiles/PUB588.pdf
The sanctioning of warfare is accompanied by a caveat of restraint, and fighters are commanded not to transgress bounds or limits. What limits?
“But if the enemy incline towards peace, do thou (also) incline towards peace, and trust in Allah: for He is One that heareth and knoweth (all things).” (Qur'an 8:61)
Abu Bakr, the first caliph after Muhammad’s death, formulated a detailed set of rules for Islamic conduct during war. He gave the following instructions to a Muslim army setting out for Syria, which was then governed by the Byzantine Empire:
Stop, O people, that I may give you ten rules for your guidance in the battlefield. Do not commit treachery or deviate from the right path. You must not mutilate dead bodies. Neither kill a child, nor a woman, nor an aged man. Bring no harm to the trees, nor burn them with fire, especially those which are fruitful. Slay not any of the enemy’s flock, save for your food. You are likely to pass by people who have devoted their lives to monastic services; leave them alone.
--http://www.strategicstudiesinstitute.army.mil/pdffiles/PUB588.pdf
***Making an aggressing nation submit to the rule of Islam after victory in battle ("Fight those who believe not in Allah nor the Last Day, nor hold that forbidden which hath been forbidden by Allah and His Messenger, nor acknowledge the religion of Truth, (even if they are) of the People of the Book, until they pay the Jizya with willing submission, and feel themselves subdued." -- Qur'an 9:29) is a different thing from converting unbelievers to Islam, which is to be done according to the following:
"Invite (all) to the Way of thy Lord with wisdom and beautiful preaching; and argue with them in ways that are best and most gracious: for thy Lord knoweth best, who have strayed from His Path, and who receive guidance." (Qur'an 16:125)
“Let there be no compulsion in religion: Truth stands out clear from Error: whoever rejects evil and believes in Allah hath grasped the most trustworthy hand-hold, that never breaks. And Allah heareth and knoweth all things.” (Qur'an 2:256).
***Allah swt does not love those who transgress in war (2:190), nor those who kill without just cause (25:68), and He loves not mischief (2:205). He is strict in punishment (2:196) but also forgiving, again and again, and generous (17:25) (22:50) (38:66).
"If you loan to Allah a beautiful loan, He will double it to your (credit), and He will grant your Forgiveness..." (64:17).
"But do good; for Allah loves those who do good." (Qur'an 2:195)
"...Allah loves those who turn to Him constantly and He loves those who keep themselves pure and clean." (Qur'an 2:222)
As a final note:
Some Western readers will probably find the Islamic rulings on war to be contradictory. It may not be clear whether they promote war or peace. Muslims believe the Quran to be divinely revealed, and Quran experts hold that the text must be understood in the spirit of its entirety, and not simply reduced to selected verses or phrases. Surah 3, al-Imran, verse 7 reads:
And those who are firmly grounded in knowledge say: “We believe in the Book; the whole of it is from our Lord:” and none will grasp the Message except men of understanding.
http://www.strategicstudiesinstitute.army.mil/pdffiles/PUB588.pdf
I have tried to give a little more context and to counterbalance the verses cited by others with more verses to give a slightly fuller, and imo, more accurate picture of Islam, inshaAllah. I can understand people's thoughts and feelings toward Islam and Muslims as I have had similar questions and concerns myself, and I continue to dig deeply and persistently in search of the answers. I hope that you will too.
~Merry