There is nothing that says non Jewish Christians are bound by the Mosaic covenant which applied to the Children of Israel. And the Abrahamic covenant is every bit as much a part of the old covenant as the Mosaic covenant and the only one that applies to non-Jewish Christians. Paul says that Christians are part of the Abrahamic covenant. It's the whole point of the book of Galatians. You are preaching the exact same message of the Judiazers who Paul bitterly criticized in Galatians. He said anyone bringing that message is accursed. Yeah, I know...I've heard how awful I am...:-)
Are Christians under any type of covenant with God or Christ?
"Are Christians under any type of covenant with God or Christ?"
Christ IS God. And those who have been born again by the regeneration of the Holy Spirit (also God)have been saved by faith and are co-heirs with Christ, their head, in the New Covenant. That is the promise which cannot be broken.