Praise be to Allah.
Imaam Muslim (may Allaah have mercy on him) said in his Saheeh: Chapter: Condemnation of the one who dies without having gone out for jihaad or having thought of doing so. Then he quoted the hadeeth of Abu Hurayrah (may Allaah be pleased with him), who said: The Messenger of Allaah (peace and blessings of Allaah be upon him) said: Whoever dies without having gone out for jihaad or having thought of doing so, dies on a branch of hypocrisy.
(Saheeh Muslim, 3533).
Al-Nawawi (may Allaah have mercy on him) said: What is meant is that the one who does this is behaving, in this regard, like the hypocrites who stay behind and do not go out for jihaad, because not engaging in jihaad is one of the branches of hypocrisy. This hadeeth also indicates that the one who intended to do an act of worship but died before he could do it is not to be condemned to the same extent as one who died without any such intention.
Al-Sindi said, in his footnotes to Sunan al-Nisaa'i: without having thought of [it] means without having said to himself, I wish I could go out for jihaad. Or it could mean that he did not intend to go out for jihaad, and the sign of intending to go out for jihaad is preparing equipment. Allaah says (interpretation of the meaning): And if they had intended to march out, certainly they would have made some preparation for it [al-Tawbah 9:64].
A person can prepare himself for jihaad in many ways, such as:
Learning the virtues of jihaad and the rulings concerning it;
preparing oneself with different kinds of acts of worship;
training oneself to make sacrifices;
forcing oneself to prefer others to oneself;
spending for the sake of Allaah;
studying and reading the biographies of mujaahideen and heroes of Islam;
studying Islamic battles;
constantly telling oneself that if jihaad is established and one has the means and is able to go for jihaad, there is no choice but to enlist;
knowing how sinful it is to run away from the battlefield or flee before the kuffaar;
studying the Seerah (biography) of the Prophet (peace and blessings of Allaah be upon him) during both the Makkan and Madani periods, and studying his battles and campaigns, to see how he conducted the jihaad in the context of his own circumstances, what he started with and how he prepared himself;
understanding that jihaad has to go through stages, beginning with the nearest enemy, until one reaches the stage of being able to fight all the mushrikeen;
being aware of the movements of hypocrisy;
waging jihaad on four fronts against ones own nafs or base self, against the Shaytaan, against the kuffaar and against the hypocrites;
understanding the importance of waging jihaad with ones wealth as well as with ones self.
Know, my brother, that it is not difficult to combine jihaad with dawah, because each of them has its own time and place. When the mujaahideen were waging their conquests, they used to call people to Allaah before the battle started. When they conquered a country, they would call its people to Islam and teach them the religion. When there was no battle or jihaad going on, the doors of dawah were still wide open, and they would make dawah to their wives, children, relatives, neighbours and all people, Muslim and non-Muslim, calling them with wisdom and beautiful preaching, and arguing with them in a way that is better. May Allaah help us and you to do that which He loves and which pleases Him. May Allaah bless our Prophet Muhammad.