Read Ecclesiastes 11:8 Using Other Translations
But if a man live many years, and rejoice in them all; yet let him remember the days of darkness; for they shall be many. All that cometh is vanity.
So if a person lives many years, let him rejoice in them all; but let him remember that the days of darkness will be many. All that comes is vanity.
When people live to be very old, let them rejoice in every day of life. But let them also remember there will be many dark days. Everything still to come is meaningless.