You tell me what it is you believe a convenant means?....
Well, this is way off topic. But a covenant in Hebrew culture was the entrance into a family - en exchange of persons, the giving of one to another. In our case, it is the entrance into the Family of God.
Hebrews would often bring outsiders into their family - or tribe - and this was done by establishing a "covenant", and was accompanied by swearing an oath and sharing a sacred meal to seal the bond. (Interestingly, the Latin word for "oath" is "sacramentum" - our sacraments are oaths: The Eucharist being the sacred meal in Christs covenant.) So, the "New Covenant" which Christ established is the means by which we enter into the Family of God (*and as a side note: The sign of the Mosaic covenant was circumcision, and the sign of Christ's covenant is Baptism.)
...The two covenants as spoken about in Galatians. We have the bond woman whom is to be cast out and we have the free woman.
Actually there are six covenants. The biblical Covenants are:
Adamic (the covenant God made with Adam),
Noahite (the covenant God made with Noah),
Abrahamic (the covenant God made with Abraham),
Mosaic (the covenant God made with Moses),
Davidic (the covenant God made with David),
and New (the covenant God in the person of Jesus made with the world)
Each successive covenant encompasses a larger and larger group of people: Two, then a family, then on and on up to the whole world. This is Gods plan, from the very beginning, of bringing more and more of the world back into his family. Thats what a covenant is: An entrance into a family.
Each successive covenant has a different sign, such as Noah's rainbow, then on to circumcision, etc.
(
As a side issue: The Ten Commandments are part of the Fourth Covenant, with Moses: We are not bound by that covenant. We are bound by Christs commands, and Saturday Sabbath keeping isnt one of them. This is a point you can make to your SDA friends.)
(*NOTE, for your information: Covenantal theology has its roots in Patristic interpretation of Scripture. Notable for the theology of history are Irenaeus's emphasis on the unity of the Old and New Testaments in "Against Heresies" and Augustine's explication of that unity through the "two cities" theme in The City of God (Books XI-XXII). Closely related are the exegetical methods by which Scripture is explained according to its "spiritual senses". These developments were organized by the scholastics into the doctrine of the "four senses," encompassing the literal sense and the three spiritual senses (allegorical, moral, and anagogical). The allegorical sense relates persons, events, and institutions of earlier covenants to those of later covenants (and especially to the New Covenant), thereby situating "spiritual" exegesis within the covenantal theology of history.)
I hope that all helps. And when you understand "covenant" and the family of God, Mary's role in our lives becomes much clearer, if you can open your heart to the Love of God's family. Do not focus on the me me me, but rather on the we we we.