The Messenger of Allah ﷺ said, "One bed is for a man, another for his wife, a third for a guest, and the fourth is for Satan."
أن رسول الله ﷺ قال: فراش للرجل، وفراش لامرأته، والثالث للضيف، والرابع للشيطان.
Muslim narrated it in the Book of Clothing (2084) from Abu Tahir Ahmad bin Amr bin Sarh, who said, Ibn Wahb informed us, Abu Hani told me, that he heard Abu Abdul-Rahman say, from Jabir bin Abdullah, that the Messenger of Allah ﷺ said, and then he mentioned it.This hadith shows the dislike of having an excessive number of sleeping mats out of vanity and boastfulness, because Satan approves of this practice and makes it appealing to the one who does it. In fact, some scholars have said that bedding beyond what is needed becomes a resting place for Satan, just as he also finds a resting place in a house whose owner does not mention Allah upon entering it.The hadith also shows that it is permissible to have separate mats, one for the husband and one for the wife, when there is a need for it, such as when the mat is too narrow to fit two people, or when one of them is ill. Sleeping with one's wife is not obligatory, but it is recommended for them to sleep on one mat, following the Prophet's ﷺ consistent practice with his wives in this regard. Still, their sleeping on one mat does not necessitate the fulfillment of marital relations.