Kalām

I believe the concept of warfare in Islam is one of the most controversial aspects of it. Therefore, I would like to explain how I understand it until now in a way that is compatible with the shariah and our natural moral intuition [fitrah]. Let me know what you think. 

Islam is the last message from God to humanity. God, having the eternal attributes of mercy and justice, desires that the world is ruled by worship of the divine and on just laws, which will lead to both happiness in this life and the next.

Islam teaches the preservation of life, truth, property, and honor. It combats the injustices and evils of murder, theft, blasphemy, and adultery by taking serious actions against them in the form of hudud [deterrent penal laws] and promotes mercy and justice between all. 

Since Islam's message is universal, it makes sense that God would command the believers to make the world a better place, by spreading the laws of God and ending evil and injustice in the world.

Therefore, a nation that rules by the just laws of God that will benefit all humanity has a moral duty to spread its influence across the world to bring different cultures, races, and people to hear the message of his true prophet and be ruled by God's laws to achieve justice.

Therefore, Islam has what is called Jihad Al-Talab. This form of jihad is understood in the following way: a united Muslim nation goes to the government of a non-Muslim nation that doesn't rule by God's just laws. They give them two choices: to accept Islam or to pay the jizya,

In both cases, the non-Muslim government ought to join the Muslim nation: either by accepting Islam itself, which makes them citizens of the Muslim nation with both rights and responsibilities under God's just laws, or by paying the jizya.

The jizya, in the philosophy of Islamic moral thinking, would be a necessity. God desires those who worship him to be sincere and not due to force. Therefore, the jizya was ordained to those who did not accept Islam, since they would be citizens of the Muslim nation.

The non-Muslims under the Muslim nation would be, according to Islam's moral philosophy, experiencing the privilege of living under a nation that rules by   justice given by God who is the all-just and merciful which will give them a happy life in this world.

Added to that is that no one would stop the Muslims from peacefully inviting the non-Muslims to Islam without force and the choice is theirs.

The jizya would be a tax given to the Muslims as compensation for their work and risking of their lives for the protection of the non-Muslims against external and internal threats and the protection of the order, justice, peace, and good life that the Muslim nation provides.

The jizya also would be enforced only on those that normally participate in the military. So, it would exclude women, children, and those who are unable to fight as a compensation for them not risking their own lives and having the Muslims be the ones who protect them.

In short, my understanding is Islam, being from God, is a command to spread justice and peace across the world. That can only happen if the Muslim nation expands and removes governments from ruling their people by evil, unholy, and unjust laws and rules these people by God laws.

This will lead to both the acceptance of Islam and being ruled in a way that makes their lives better and happier or the non-acceptance of Islam while still being ruled by the laws of god which would still make their lives better in exchange for quite a small tax.

This tax would not be exclusive to this, since Muslims also pay the zakat and are ordered to work for the muslim nation to keep the order of justice in the land. The non-Muslims under Muslim rule, however, do not have these responsibilities.

I tried explaining this as best as I could and I hope God teaches me his wisdom in this world.