The miracle of the moment, the miracle of Advent is that we are all treated as the eldest son. Think about this for a moment. The inheritance is coming from God the Father, whose only son is Jesus Christ. So, what we are being told here is that the miracle of the moment, the miracle of advent is that we are treated, by God, as though we are Jesus Christ himself.
https://www.portstewartpresbyterian.org/sermons/covenant-god-pursues/ https://www.youtube.com/watch?v=213Ebx-YuhQ&t=5s
Harvest is the opportunity for us to stop and realise just how good God is to us and to give thanks. That God is with us, that we have indeed tasted that God is good, but maybe we just need to remember how good that taste is.