Sahih al-Bukhari Book 68, Hadith 50
(a companion of Allah's Messenger (ﷺ)) Allah's Messenger (ﷺ), holding out his middle and index fingers, said, "My
advent and the Hour's are like this (or like these)," namely, the period between his era and the Hour is
like the distance between those two fingers, i.e., very short.
Allah's Messenger (ﷺ) said, "Shall I tell you of the best families among the Ansar?" They (the people) said, "Yes, O Allah's Messenger (ﷺ)!" The Prophet (ﷺ) said, "The best are Banu- An-Najjar, and after them are Banu `Abdil Ash-hal, and after them are Banu Al-Harith bin Al-Khazraj, and after them are Banu Sa`ida." The Prophet (ﷺ) then moved his hand by closing his fingers and then opening them like one throwing something, and then said, "Anyhow, there is good in all the families of the Ansar. "
The Prophet (holding out his ten fingers thrice), said, "The month is thus and thus and thus," namely thirty days. Then (holding out his ten fingers twice and then nine fingers), he said, "It may be thus and thus and thus," namely twenty nine days. He meant once thirty days and once twenty nine days.