A man asked, "Messenger of Allah, tell me about jihad and military expeditions."He replied, "Abdullah bin Amr, if you fight with patience and seeking reward from Allah, Allah will resurrect you as one who was patient and sought His reward. But if you fight to show off and to boast of numbers, Allah will resurrect you as one who showed off and boasted. Abdullah bin Amr, in whatever state you fight or are killed, Allah will resurrect you in that very state."
حدثنا مسلم بن حاتم الأنصاري حدثنا عبد الرحمن بن مهدي حدثنا محمد بن أبي الوضاح عن العلاء بن عبد الله بن رافع عن حنان بن خارجة عن عبد الله بن عمرو قال
يا رسول الله أخبرني عن الجهاد والغزو فقال يا عبد الله بن عمرو إن قاتلت صابرا محتسبا بعثك الله صابرا محتسبا وإن قاتلت مرائيا مكاثرا بعثك الله مرائيا مكاثرا يا عبد الله بن عمرو على أي حال قاتلت أو قتلت بعثك الله على تلك الحال
No references are available.
Its chain of transmission is hasan. Hakim reported it in 5/2, 86 and graded it sahih, and Dhahabi agreed with him.