Between the two blows (of the Trumpet), there will be (an interval of) forty. The people said: O Abu Hurayrah, do you mean forty days? He said: I cannot say anything

عن أبي هريرة رضي الله عنه قال: قال رسول الله صلى الله عليه وسلم : «بين النفختين أربعون» قالوا: يا أبا هريرة أربعون يومًا؟ قال: أَبَيْتُ. قالوا: أربعون سنة؟ قال: أَبَيْتُ. قالوا: أربعون شهرا؟ قال: أَبَيْتُ. «ويَبْلَى كل شيء من الإنسان إلا عَجْبُ الذَّنَب، فيه يُرَكَّبُ الخلق، ثم يُنْزِلُ الله من السماء ماء فَيَنْبُتُونَ كما يَنْبُتُ الْبَقْلُ».

Abu Hurayrah (may Allah be pleased with him) reported that the Messenger of Allah (may Allah's peace and blessings be upon him) said: "Between the two Blows (of the Trumpet), there will be (an interval of) forty." The people said: "O Abu Hurayrah, do you mean forty days?" He said: "I cannot say anything." They said: "Do you mean forty years?" He said: "I cannot say anything." They said: "Do you mean forty months?" He said: "I cannot say anything." (The Prophet added) "Everything of the human body will perish except the end of the coccyx (tailbone), and from that part, Allah will reconstruct the whole body. Then Allah will send down water from the sky, and the people will grow like green vegetables."

Source · Narrated by Bukhari & Muslim

From the Hadith Encyclopedia (hadeethenc.com).