Sayyiduna Abu Hurayrah (may Allah be pleased with him) said that the Prophet (peace and blessings be upon him) said: "The slave of the dirham, the dinar and the cloak is ruined. If he is given, he is pleased; and if he is not given, he becomes displeased. May such a person be wretched and humiliated; if a thorn pricks him, may it not be removed. And glad tidings are for the man who holds the reins of his horse in the path of Allah, his hair dishevelled and his feet covered in dust. If he is assigned to the rear of the army, he serves there; and if he is posted with the guard, he stands guard. If he asks permission, it is not granted to him, and if he intercedes for someone, his intercession is not accepted. Glad tidings for him, glad tidings for him!"
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18498