And Abu Darda (may Allah be pleased with him) said that you fight (in battle) because of your (righteous) deeds, and the statement of Allah the Exalted (in Surah As-Saff) «يا أيها الذين آمنوا لم تقولون ما لا تفعلون * كبر مقتا عند الله أن تقولوا ما لا تفعلون * إن الله يحب الذين يقاتلون في سبيله صفا كأنهم بنيان مرصوص‏» "O you who have believed, why do you say what you do not do? It is most hateful in the sight of Allah that you say what you do not do. Indeed, Allah loves those who fight in His cause in rows as though they are a solid structure."

Narrated Al-Bara: A man whose face was covered with an iron mask (i.e. clad in armor) came to the Prophet and said, "O Allah's Apostle! Shall I fight or embrace Islam first? "The Prophet said, "Embrace Islam first and then fight." So he embraced Islam, and was martyred. Allah's Apostle said, A Little work, but a great reward. "(He did very little (after embracing Islam), but he will be rewarded in abundance).