The Book of Colossians chapter 2:
16 Therefore do not let anyone condemn you in matters of food and drink or of observing festivals, new moons, or sabbaths. 17 These are only a shadow of what is to come, but the substance belongs to Christ.
Jesus is the substance behind all Gods feasts.
The converse is able to be posed to you. If God said the feasts are forever who are you to tell Christians who are grafted into the Tribe of Judah to disobey God?
The Epistle to the Galatians chapter 3:29 And if you are Christ's, then you are Abraham's offspring, heirs according to promise.
The Book of the Acts of the Apostles chapter 2:39 For the promise is for you and for your children and for all who are far off, everyone whom the Lord our God calls to himself.”