How so.
The spring feasts were fufilled by the Messiah (Jesus) coming as God's suffering servant and dying for the sins of the world
and rising again (first fruits) and Pentecost salvation being offerered to everyone
Summer the time of the harvest
Fall feasts -Jesus returns as the victorious king for judgement and to establish his kingdom fulfilling all the prophecies of Messiah which remained unfufilled after first coming
This age comes to an end.