Hazrat Abu Huraira (may Allah be pleased with him) narrated that the Messenger of Allah (peace and blessings be upon him) said: There will be an interval of forty between the two trumpet blasts. The students of Hazrat Abu Huraira (may Allah be pleased with him) asked, "Are forty days meant?" He replied, "I do not know." Then the students asked, "Are forty months meant?" He replied, "I do not know." The students asked, "Are forty years meant?" He replied, "I do not know." He said, "Then Allah, the Exalted, will send down water from the sky, because of which all the dead will be revived, just as vegetation grows from water. At that time, every part of the human body will have decayed except the tailbone, and from it, on the Day of Resurrection, all creatures will be recreated."