Kalam
Many muslims like to say "Islam forbids the killing of innocent people", I'm asking for someone to prove unequivocally using Islamic scripture, that non muslims are innocent.
http://www.usmessageboard.com/religion-and-ethics/81748-islam-forbids.html
What's forbidden by the Ahl us-Sunnah is killing certain types of people mentioned by the four madhahib in their major works of fiqh. The Hanafi madh'hab specifically prohibits killing women, children, the elderly, various kinds of physically disabled people, travelers, the mentally handicapped (Bidaa'iʾ w'as-Sinaa'iʾ

as well as laborers and farmers and the diseased (Al-Mabsut.) The Maliki madh'hab mentions women, children, clergy (Ar-Risala,) the elderly and the infirm (Al-Muwatta.) Hanbalis list women, children, the elderly, monks, the disabled, farmers, slaves, sages, and those whose gender can't readily be discerned (Al-Mughni, Al-Furu'.) The Shafi'i fuqaha all mentioned women and children; Imam ash-Shafi'i himself mentions monks (Al-Umm) and later fuqaha' made mention of many of the kinds of people named by the other madhahib. Each of these categories of people comes from the commands of Muhammad (s.) or Abu Bakr (r.) or 'Umar ibn al-Khattab (r.) as preserved in the six Sunni kutub ul-hadeeth. The general principle of all of these prohibitions can be summed up with the comment of al-Khalifah 'Umar ibn 'Abd ul-'Aziz:
وقال عمر بن عبد العزيز في قول الله تبارك وتعالى ﴿وقاتلوا في سبيل الله الذين يقاتلونكم ولا تعتدوا﴾ قتل النساء والصبيان من ذلك، ومن لم ينصب الحرب منهم
And said 'Umar bin 'Abd ul-'Aziz in the Words of Allah the Blessed and Exalted, "(And fight in the way of Allah those who fight you, and don't transgress) ...[meaning] the killing of women and children and those who don't wage the war/act with hostility."
If anybody participates willingly in the enemy war effort (whether directly or through providing intelligence, supplies, propaganda, etc.), it becomes permissible to engage them. If the enemy surrounds itself with non-combatants, collateral damage is usually excused so long as the fighters are targeted. Among the "Salafiyyah"/ghayr muqallid, some such as Ibn Uthaymeen supported killing civilians if the enemy does this, and others such as Abu Basir at-Tartusi reject this.