The Messenger of Allah ﷺ said, "Allah has prepared for the one who goes out in His path, whom nothing brings out except striving in My path, faith in Me, and belief in My messengers, that I guarantee I will admit him into Paradise, or return him to the dwelling from which he set out, having gained whatever reward or spoils he obtained."Then he said, "By the One in whose hand is my soul, were it not that I would cause hardship to the Muslims, I would never stay behind from any expedition setting out in the path of Allah. But I do not have the means to carry them, nor do they have the means to follow me, nor would they be content to remain behind after me. By the One in whose hand is the soul of Muhammad, I would love to fight in the path of Allah and be killed, then fight and be killed, then fight and be killed."
حدثنا أبو بكر بن أبي شيبة حدثنا محمد بن الفضيل عن عمارة بن القعقاع عن أبي زرعة
قال رسول الله ﷺ أعد الله لمن خرج في سبيله لا يخرجه إلا جهاد في سبيلي وإيمان بي وتصديق برسلي فهو علي ضامن أن أدخله الجنة أو أرجعه إلى مسكنه الذي خرج منه نائلا ما نال من أجر أو غنيمة ثم قال والذي نفسي بيده لولا أن أشق على المسلمين ما قعدت خلاف سرية تخرج في سبيل الله أبدا ولكن لا أجد سعة فأحملهم ولا يجدون سعة فيتبعوني ولا تطيب أنفسهم فيتخلفون بعدي والذي نفس محمد بيده لوددت أن أغزو في سبيل الله فأقتل ثم أغزو فأقتل ثم أغزو فأقتل
Bukhari narrated it in the chapter on Faith, in the section on jihad being part of faith, hadith no. 36, and Muslim narrated it in the chapter on Leadership, in the section on the merit of jihad and going forth in the path of Allah, hadith no. 1876, from the hadith of Umarah, in both lengthy and abridged forms.