Firstly, I apologize for the English. I'm using English, because most people have some knowledge of English. And not everybody masters Arabic or other languages, and I may not know your native language. I'll try to keep this short.
You've been told, that jihad for Islam is rewarding, and compulsory if the Ummah is in peril. And in Syria and Iraq, Muslims seem to be in danger of persecution and death. But what happens next? A group of people, former Iraqi and Syrian military personnel, and former intelligence workers, trained by the CIA, graps power over several cities and roads in Iraq and Syria. They establish a state that should become a legitimate Islamic Khilafah, ruled with Shariah law. And, so it seems, start a media campaign to attract Muslim immigrants. And, worse, start another media campaign displaying their conquests on the battle field. In practice, the latter is open display of public executions of 'ennemies'. Especially decapitation of Westerners is their fav item. Now, even Islamic Westerners aren't spared. Maybe it's understandable, if former torturers from the Iraqi or US army receive this treatment. But why Muslims are now beheading other Muslims, sometimes caregivers and business people, who sometimes converted to Islam with the best of intentions, is an issue beyond my comprehension. It resembles a cheap cartoon show: Westerners decapitating other Westerners for the sake of Islam in Iraq, and often they both present themselves as Muslims. In many cases, the best young people of a nation now travel to f★¿ IS, and risk decapitation, nevertheless. Well-educated people with high integrity. Doesn't that seem like utter wastry? Wastry for a case with, to foreigners, many unknowns. You don't know the local situation. In how far does it justify Islamic retribution, and who is IS really? how Islamic is their behavior?
A few things you should know, before you leave your home for jihad: You're not allowed to oppress, torture, or persecute people. You're not allowed to go on jihad, if your parents are still alive. They have more right over you than a war in a strange environment. Your death will cause them grief for the rest of their lives. Is that what you want? You're certainly allowed to fight for your own home, family, and land, but fighting for other people's land is, naturally, a different matter. And you're not allowed to kill women and children. IS mocks precisely those issues, which are important to Muslims and everybody else. So do yourselves and everybody else a favor, and do not interfere in what isn't your business or expertise. Here are some Qur'anic verses and some ahadith:
'And whoever kills a believer intentionally, his punishment is hell; he shall abide in it, and Allah will send His wrath on him and curse him and prepare for him a painful chastisement.' Qur'an 4:93
' If Allah were to punish men for their wrong-doing, He would not leave, on the (earth), a single living creature: but He gives them respite for a stated Term: When their Term expires, they would not be able to delay (the punishment) for a single hour, just as they would not be able to anticipate it (for a single hour).'Qur'an 16:61
'Seest thou not that We have set the devils on the disbelievers to confound them with confusion? So make no haste against them, for We but count out to them a (limited) number (of days). Qur'an 19:83,84
'Allah forbids you not, with regard to those who fight you not for (your) Faith nor drive you out of your homes, from dealing kindly and justly with them: for Allah loveth those who are just. Allah forbiddeth you only those who warred against you on account of religion and have driven you out from your homes and helped to drive you out, that ye make friends of them. Whosoever maketh friends of them - (All) such are wrong-doers.' Qur'an 60:8,9
Hadiths transmitted by Sahih Bukhari, Volume 9, Book 84, Number 61:
Narrated 'Aisha: A group of Jews asked permission to visit the Prophet (and when they were admitted) they said, "As-Samu 'Alaika (Death be upon you)." I said (to them), "But death and the curse of Allah be upon you!" The Prophet said, "O 'Aisha! Allah is kind and lenient and likes that one should be kind and lenient in all matters." I said, "Haven't you heard what they said?" He said, "I said (to them), 'Wa 'Alaikum (and upon you).Volume 9, Book 84, Number 68:
Narrated Yusair bin 'Amr: I asked Sahl bin Hunaif, "Did you hear the Prophet saying anything about Al-Khawarij?" He said, "I heard him saying while pointing his hand towards Iraq. "There will appear in it (i.e, Iraq) some people who will recite the Quran but it will not go beyond their throats, and they will go out from (leave) Islam as an arrow darts through the game's body.' "Volume 9, Book 88, Number 180:
Narrated Abu Huraira:Volume 9, Book 88, Number 184:
I heard the truthful and trusted by Allah (i.e., the Prophet ) saying, "The destruction of my followers will be through the hands of young men from Quraish."
Narrated 'Abdullah and Abu Musa: The Prophet said, "Near the establishment of the Hour there will be days during which Religious ignorance will spread, knowledge will be taken away (vanish) and there will be much Al-Harj, and Al-Harj means killing."Volume 9, Book 89, Number 257:
Narrated Ibn 'Abbas:
The Prophet said, "If somebody sees his Muslim ruler doing something he disapproves of, he should be patient, for whoever becomes separate from the Muslim group even for a span and then dies, he will die as those who died in the Pre-lslamic period of ignorance (as rebellious sinners). (See Hadith No. 176 and 177)
Volume 9, Book 89, Number 329:
Narrated Jabir bin Samura: I heard the Prophet saying, "There will be twelve Muslim rulers (who will rule all the Islamic world)." He then said a sentence which I did not hear. My father said, "All of them (those rulers) will be from Quraish."Hadiths by Sahih Muslim, Book 019, Number 4320:
It is narrated by Ibn 'Umar that a woman was found killed in one of these battles; so the Messenger of Allah (may peace be upon him) forbade the killing of women and childrenBook 032, Number 6184:
Abdullah b. 'Anir reported that a person came to Allah's Apostle (may peace be upon him) and sought permission (to participate) in Jihad, whereupon he (the Holy Prophet) said: Are your parents living? He said: Yes. Thereupon he (the Holy Prophet) said: You should put in your best efforts (in their) service.Book 032, Number 6248:
Jabir b. Abdullah reported that Allah's Messenger (may peace be upon him) said: Be on your guardagainst committing oppression, for oppression is a darkness on the Day of Resurrection, and be on your guard against pettimindedness for pettimindedness destroyed those who were before you, as it incited them to shed blood and make lawful what was unlawful for them.
Book 032, Number 6327:
'Urwa reported on the authority of his father that Hisham b. Hakim b. Hizam happened to pass by some people in Syria who had been made to stand in the sun and olive-oil was being poured upon their heads. He said: What is this? It was said: They are being punished for (not paying) the Kharaj (the government revenue). Thereupon he said: Allah would punish those who torment people in this world (without any genuine reason).Finally, there's some rumor about a hadith said to have predicted, perhaps, ISIS:
Abu Abdullah Nuaim Ibn Hammad on a chain of transmission on the authority of Al Zuhari who said " The black flags will come from the East, led by mighty men, with long hair and beards, their surnames are taken from the names of their home towns (i.e. Khosti or from Khost etc.) and their first names are from a "Kunya"
(Asmal Masalik Lieyyam Mahdiyy Maliki Li Kull-id Dunya Biemrillah-il Malik, Qalda bin Zayd)
I'm not sure how reliable it is, but want to mention it anyway.
University of Southern California USC-MSA Center for Muslim-Jewish Engagement (Compendium of Muslim Texts) http://www.usc.edu/org/cmje