umar b. al-khattab, with whom allah is pleased, said: 'i entered the messenger's house, may allah exalt his mention, and i found him sitting on a mat. he had a leather pillow stuffed with fibers. he had a pot of water by his feet, and there was some clothes hung on the wall. his side had marks due to the mat that he lay on. umar, with whom allah is pleased, wept when he saw this, and the messenger, may allah exalt his mention, asked him: 'why do you weep?' umar said: 'o prophet of allah! khosrau and caesar enjoy the best of this world, and you are suffering in poverty?!' he said: 'aren't you pleased that they enjoy this world, and we will enjoy the hereafter?' (bukhari #4629)