It is also narrated in the two books (Al Bukha^ri and Muslim): A man said: O Allah s Messenger (pbuh)! Inform me of a thing that is equal to Jihad (in Allahs Cause)! Allahs Messenger (pbuh) said, You cannot (do that). The man said: Inform me of that. Allahs Messenger (pbuh) said: Can you observe Saum (fast) continuously without eating or drinking (at all) and stand continuously in Salat (prayer) from the time the Mujahidin go out for Jihad (till the time they return back home)? The man replied, No. Allahs Messenger said: That is (the thing) which is equal to Jihad. Likewise Allahs Messenger (pbuh) said: I) The souls of the martyrs are in the green birds dwelling in Paradise wherever they like. 2) That all their sins and faults are forgiven. 3) That he can intercede with Allah (swt) for seventy (70) of his family members. 4) That he will come secure on the Day of Resurrection from the great terror. 5) That he will not feel the agonies and distress of death. 6) That he will not be horrified by the (great) Gathering (on the Day of Resurrection). 7) That he does not feel the pain of the killing except like that of a pinch.
Then fight, (O Muhammad pbuh), in the Cause of Allah, you are not tasked (held responsible) except for yourself, and incite the believers (to fight along with you), it may be that Allah will restrain the evil might of the disbelievers. And Allah is Stronger in might and Stronger in punishing. (V.4:84).
O you who believe! What is the matter with you,that when you are asked to march forth in the Cause of Allah (i.e. go for Jihad), you cling heavily to the earth? Are you pleased with the life of this world rather than the Hereafter? But little is the enjoyment of the life of this world as compared with the Hereafter. (V.9:38).
Similarly Allah (swt) disapproved of those who abandoned Jihad (i.e. they did not go for Jihad) and attributed to them hypocrisy and disease in their hearts, and threatened (all) those who remain behind from Jihad and sit (at home) with horrible punishment. He (Allah swt) accused them with the most ugly descriptions, rebuked them for their cowardice and spoke against them (about their weakness and their remaining behind) as He said: If you march not forth, He will punish you with a painful torment and will replace you by another people and you cannot harm Him at all, and Allah is Able to do all things (V.9:39).
How often a small group overcame a mighty host by Allahs leave? And Allah is with the patient. (V.2:249