Musnad Ahmad 3684

It was narrated from 'Abdullah (رضي الله عنه) that The Prophet (ﷺ) said: "The millstone of Islam will turn for thirty-five (years) or thirty-six or thirty-seven, then if they perish (after deviating) they will meet the same fate as those who perished (before them), but is they persist (in following the right path) then they will be in a good state for seventy years."