It can be in the form of reporting a tradition, authoring a book, seeking religious knowledge, learning any other advantageous field of science, setting aright matters of difference among disputing parties, enjoining the right, or forbidding the wrong in addition to self-sacrifice and fighting for the sake of Almighty Allah. In Muslim jurisprudential terminology, the word jihad usually means fighting for the sake of Almighty Allah with weapons and readiness to embrace injury, death and martyrdom.
Almighty Allah has imposed jihad in this sense on every Muslim (male) individual under certain conditions. Therein it becomes obligatory upon such individuals to expose themselves to death in defense of themselves, Islam, and persecuted people.
In this regard, the Holy Qur'an states: كُتِبَ عَلَيْكُمُ الْقِتَالُ وَهُوَ كُرْهٌ لَكُمْ وَعَسَى أَنْ تَكْرَهُوا شَيْئًا وَهُوَ خَيْرٌ لَكُمْ وَعَسَى أَنْ تُحِبُّوا شَيْئًا وَهُوَ شَرٌّ لَكُمْ(216) Fighting is enjoined upon you, and it is an object of dislike to you. It may be that you dislike a thing while it is good for you and it may be that you love a thing while it is evil for you.
(2:216) أُذِنَ لِلَّذِينَ يُقَاتَلُونَ بِأَنَّهُمْ ظُلِمُوا وَإِنَّ اللَّهَ عَلَى نَصْرِهِمْ لَقَدِيرٌ (39) الَّذِينَ أُخْرِجُوا مِنْ دِيَارِهِمْ بِغَيْرِ حَقٍّ إِلَّا أَنْ يَقُولُوا رَبُّنَا اللَّهُ وَلَوْلَا دَفْعُ اللَّهِ النَّاسَ بَعْضَهُمْ بِبَعْضٍ لَهُدِّمَتْ صَوَامِعُ وَبِيَعٌ وَصَلَوَاتٌ وَمَسَاجِدُ يُذْكَرُ فِيهَا اسْمُ اللَّهِ كَثِيرًا وَلَيَنْصُرَنَّ اللَّهُ مَنْ يَنْصُرُهُ إِنَّ اللَّهَ لَقَوِيٌّ عَزِيزٌ (40) Permission to fight is given to those upon whom war is made because they are oppressed and, most surely, Allah is well able to assist them; those who have been expelled from their homes without a just cause except that they say, “Our Lord is Allah.” Had there not been Allah's repelling some people by others, certainly there would have been pulled down cloisters, churches, synagogues, and mosques in which Allah's name is much remembered.
Surely, Allah will help him who helps His cause. Most surely, Allah is Strong, Mighty.