Musnad Ahmad 830:0

Narrated Abu Bakrah Nufay' ibn al-Harith ibn Kaladah: The Prophet (ﷺ) said: "Time has completed its cycle in the form of the day that Allah created the heavens and the earth. The year consists of twelve months, of which four are sacred: three consecutive months—Dhu al-Qa'dah, Dhu al-Hijjah, and al-Muharram—and Rajab of Mudar, which is between Jumada and Sha'ban." He then said: "What day is this?" We said: "Allah and His Messenger know best." He remained silent until we thought he might name it by another name. He said: "Is it not the Day of Sacrifice (Yawm al-Nahr)?" We said: "Yes." He said: "What month is this?" We said: "Allah and His Messenger know best." He remained silent until we thought he might name it by another name. He said: "Is it not the month of Dhu al-Hijjah?" We said: "Yes." He said: "What land is this?" We said: "Allah and His Messenger know best." He remained silent until we thought he might name it by another name. He said: "Is it not the Sacred Land (al-Balad al-Haram)?" We said: "Yes." He said: "Indeed, your blood, your wealth, and your honor are sacred to you, like the sanctity of this day of yours, in this month of yours, in this land of yours. You will surely meet your Lord, and He will ask you about your deeds. Do not return to being disbelievers after me, striking the necks of one another." "Let those who are present convey it to those who are absent, for perhaps the one to whom it is conveyed will understand it better than some of those who heard it."