Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever fights in the path of Allah even for the length of a camel's fuwaq, Paradise becomes binding for him. Whoever sincerely asks from his heart to be killed (martyrdom), then dies or is killed, will have the reward of a martyr. And whoever is wounded in the path of Allah or struck by some calamity, it will come on the Day of Resurrection flowing more abundantly than it ever did, its colour like saffron and its fragrance like musk."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17342