Mukhtasar Bukhari (Abridged) 368 — Book of Prayer Times

Narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Noble Prophet (peace and blessings be upon him) once offered the Isha prayer in the last part of his life... till the end (has passed, see the Book: Statement of Knowledge... Chapter: Talking about knowledge at night...). And in this hadith, Sayyiduna Ibn Umar (may Allah be pleased with them both) narrates that the Noble Prophet (peace and blessings be upon him) said: "Indeed, after one hundred years, none of those who are on the earth today will remain." By this, the Prophet (peace and blessings be upon him) meant that this generation (era) will pass away.