Sahih al-Bukhari 4212 (Book 64, Hadith 428)

Narrated Abu Bakra: The Prophet (ﷺ) said, “Time has taken its original shape which it had when Allah created the Heavens and
the Earth. The year is of twelve months, four of which are sacred, and out of these (four) three are in
succession, i.e. Dhul-Qa’da, Dhul-Hijja and Al-Muharram, and the fourth is Rajab which is named
after the Mudar tribe, between (the month of) Jumaida (ath-thania) and Sha’ban.” Then the Prophet (ﷺ)
asked, “Which is this month?” We said, “Allah and His Apostle know better.” On that the Prophet (ﷺ)
kept quiet so long that we thought that he might name it with another name. Then the Prophet (ﷺ) said,
“Isn’t it the month of Dhul-Hijja?” We replied, “Yes.” Then he said, “Which town is this?” “We
replied, “Allah and His Apostle know better.” On that he kept quiet so long that we thought that he
might name it with another name. Then he said, “Isn’t it the town of Mecca?” We replied, “Yes, ”
Then he said, “Which day is today?” We replied, “Allah and His Apostle know better.” He kept quiet
so long that we thought that he might name it with another name. Then he said, “Isn’t it the day of An-
Nahr (i.e. sacrifice)?” We replied, “Yes.” He said, “So your blood, your properties, (The sub-narrator
Muhammad said, ‘I think the Prophet (ﷺ) also said: And your honor..) are sacred to one another like the
sanctity of this day of yours, in this city of yours, in this month of yours; and surely, you will meet
your Lord, and He will ask you about your deeds. Beware! Do not become infidels after me, cutting
the throats of one another. It is incumbent on those who are present to convey this message (of mine)
to those who are absent. May be that some of those to whom it will be conveyed will understand it
better than those who have actually heard it.” (The sub-narrator, Muhammad, on remembering that
narration, used to say, “Muhammad spoke the truth!”) He (i.e. Prophet) then added twice, “No doubt!
Haven’t I conveyed (Allah’s Message) to you?”