Musnad Ahmad 32:477

Abu al-Nadr narrated to us, al-Mubarak narrated to us, from al-Hasan, from Anas ibn Malik, who said: I entered upon the Messenger of Allah (peace and blessings of Allah be upon him) while he was lying on a bed woven with strips, and under his head was a pillow of leather, stuffed with palm fibers. A group of his companions entered upon him, and Umar entered. The Messenger of Allah (peace and blessings of Allah be upon him) shifted slightly, and Umar saw that there was no garment between his side and the strips, and the strips had left a mark on the side of the Prophet (peace and blessings of Allah be upon him). Umar wept, so the Prophet (peace and blessings of Allah be upon him) said to him: "What makes you weep, O Umar?" He said: "By Allah, I do not weep except that I know you are more honorable to Allah than Chosroes and Caesar, yet they revel in the world in what they revel in, while you, O Messenger of Allah, are in the state that I see." The Prophet (peace and blessings of Allah be upon him) said: "Are you not pleased that they have the world and we have the Hereafter?" He said: "Yes." He said: "It is indeed so."