The word "Jihad" was mentioned many times in the Qur'an and in the Sunnah such as Allah's Saying:"O You who believe! Shall I guide you to a trade that will save you from a painful torment? * That you believe in Allâh and His Messenger (Muhammad peace be upon him), and that you strive hard and fight in the Cause of Allâh with your wealth and your lives, that will be better for you, if you but know!" And Allah's Saying: "So, obey not the disbelievers, but strive against them (by preaching) with the utmost endeavor with it (the Qur'ân)." 
As for the Sunnah, the Prophet (peace be upon him) said: "The root of this matter (foundation) is Islam, its pillar (mainstay is) Salah (the prayer), and its highest point is Jihad (fighting in the Cause of Allah)." 
He also said: "Allah guarantees him who strives in His Cause and whose motivation for going out is nothing but Jihad in His Cause and belief in His Word, that He will admit him into Paradise (if martyred) or bring him back to his dwelling place, whence he has come out, with what he gains of reward and booty." 
What is Jihad, its reality, its objectives, and its rulings? What is our role in today's world?
To answer these questions, I have to say that the meaning of Jihad literally and idiomatically:
Scholar Ibn Hajar Al `Asqalany said: "The meaning of Jihad in the language is hardship. Idiomatically, exerting efforts in fighting the unbelievers. It is also called for fighting oneself, Satan, and the immoral people." 
Then he mentioned its types and categories.
Types of Jihad and its categories:
Imam Ibn Al Qayyim explained these types and categories and put them in four categories:
First, fighting one's desires.
Second, fighting of Satan.
Third, fighting the infidels.
Fourth, fighting the hypocrites.
Fighting one's vain desires is divided into four categories,
First: Learning the true religion.
Second: Acting according to it.
Third: Calling to it.
Fourth: Observing patience to do so.
He classified fighting Satan into two categories:
First, refuting doubts by knowledge and certainty.
Second: Fighting vain desires by observing patience and forbearance.
Then he classified fighting infidels and hypocrites into four categories, fighting them by heart. Second: By tongue. Third: By money. Fourth: By oneself.
Moreover, he added a new category which is fighting the oppressors, people of whims, sins, and deniable acts. He classified it into three categories: Changing error by hand if a person has the power to do so, but if he is unable, he should fight by the tongue, and if he is unable to do so, he should fight by heart.
As for fighting enemies, its goal is conspicuous and does not need any justification because all legislations and reasons admit it because the forces of evil and error are working hard and the battle between good & evil and guidance & error is continuous; moreover the conflict between the forces of faith and oppression is still going since Allah has created man. Evil is wild and error is armed, and they use their forces with no mercy to seduce the people and prevent them from doing goodness, therefore, faith, goodness, and the truth should have some power to defend themselves against seditions. Allah did not want to leave faith, goodness, and the truth unarmed depending on the power of faith, but the material force of evil can shake the hearts, seduce souls, and distort natural despositions. Therefore, the believers were not left for sedition but after they had taken their provisions and got ready for assistance, then Jihad was ordained for them. Allah (Glory be to Him) says: "Permission to fight (against disbelievers) is given to those (believers) who are fought against, because they have been wronged; and surely, Allâh is Able to give them (believers) victory * Those who have been expelled from their homes unjustly only because they said: "Our Lord is Allâh." For had it not been that Allâh checks one set of people by means of another, monasteries, churches, synagogues, and mosques, wherein the Name of Allâh is mentioned much would surely have been pulled down. Verily, Allâh will help those who help His (Cause). Truly, Allâh is All-Strong, All-Mighty. * Those (Muslim rulers) who, if We give them power in the land, (they) enjoin Iqamat-as-Salât. [i.e., to perform the five compulsory congregational Salât (prayers) (the males in mosques)], pay the Zakât and they enjoin Al-Ma`rûf (i.e., Islâmic Monotheism and all that Islâm orders one to do), and forbid Al-Munkar (i.e., disbelief, polytheism and all that Islâm has forbidden) [i.e., they make the Qur'ân as the law of their country in all the spheres of life]. And with Allâh rests the end of (all) matters (of creatures)." 
Allah says:"So they routed them by Allâh's Leave and Dâwûd (David) killed Jâlût (Goliath), and Allâh gave him [Dâwûd (David)] the kingdom [after the death of Tâlût (Saul) and Samuel] and Al-Hikmah (Prophethood), and taught him of that which He willed. And if Allâh did not check one set of people by means of another, the earth would indeed be full of mischief. But Allâh is full of bounty to the 'Alamîn (mankind, jinn and all that exists)."
Hence, the purpose of Jihadu-Daf` [Fighting enemies] is to secure the freedom of creed and worship, and to protect the rites and the places of worship including the temples of the Jews, the Christians, and monks. It is not made to achieve worldly ambitions, temporary benefits, and personal interests but for the reformation of life, stopping corruption, and preventing oppression and tyranny. A man asked the Prophet (peace be upon him): "A man fights for war booty; another fights for fame and a third fights for showing off; which of them fights in Allah's Cause? The Prophet (peace be upon him) said: "He who fights that Allah's Word (i.e. Islam) should be superior, fights in Allah's Cause." 
As for the Jihad which opens new countries for Islam, its purpose is to remove obstacles which prevent people from embracing Islam and stand as a hindrance between them and guidance, and deprive them of the best blessing which Allah granted the people through His Prophets and Messenger, which is Islam and guidance.
 [Surat As-Saf: 10 - 11].
 [Surat Al Furqan: 52].
 [Reported by Ahmad (5/231, 246), At-Tirmidhy No. 2616, and Ibn Majah 3973 on the authority of Mu`adh ibn Jabal and its chain of narration is good].
 [Reported by Al Bukhari (8/188) Muslim, others on the authority of Abu Hurayrah.
 [Fathul-Bary (6/3)].
 Excerpted from Zad Al Ma`ad (3/9 11).
 Excerpted from the book of Fi Zhilal Al Qur'an [in the shade of the Qur'an — 4/2424 by the great writer Sayyid Qutb (may Allah be merciful with him).
 [Surat Al Hajj: 39 - 41].
 [Surat Al Baqarah: 251].
 [Reported by Ahmad (4/303 and 397), Al Bukhari (3/206), Muslim (1513), and Ibn Majah (2783)].
Please write: COMMENT in this box to verify that you are human