The author reminds us that "Marriage was always meant to point us to the intimate, committed relationship God wants us to enjoy with him." I don't know about you, but that speaks a great deal to me. Remember that everything we are - including our character - is because of how God made us AND He made us in His image . . . so all the goodness in us, all the good things for us is to make us more like him.
We know that God loved Abram (remember last week's covenant where God walked the pathway of blood alone while He put Abram to sleep? If not, go back and read that blog). We know that God told Abram He would make his offspring too many to count. BUT . . . where are they? Well . . . in Genesis 16 we learn that Sarai and Abram are about to take things into their own hands. Isn't that often like us? We think God needs help so we jump in ahead of him?
Sarai has an Egyptian slave / maid, Hagar. (Remember after Pharoah learned that Abram had lied about Sarai being his sister? Once he found out he told Abram to take his wife and all his possessions and LEAVE. Well, Hagar was likely given to Sarai as a handmaiden [one of her possessions] when she was with Pharaoh in Egypt.) Sarah gave Hagar to Abraham - to take her as a wife - to produce an heir. He had a son with Hagar - his name was Ishmael. This was an acceptable practice of the time BUT . . . this is not what God wanted AND He had not asked for help!
God tells Abraham, "Every male among you shall be circumcised. You shall be circumcised in the flesh of your foreskins, and it shall be a sign of the covenant between me and you . . . any uncircumcised male who is not circumcised in the flesh of his foreskin shall be cut off from his people; he has broken my covenant." (Genesis 17:10b-14)
If we are offspring of Abraham, why aren't we still circumcising our little boys eight days after they are born? The circumcision Abraham was commanded to carry out pointed to a cleansing to come that would not only mark the body but also change the heart. Rather than being marked as belonging to God by circumcision, we are marked as belonging to God in a new way - through baptism. "Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit" (Matthew 28:19)
Circumcision was only for the males to remind them if they did not keep the covenant and obey the laws they would ruin their relationship with God and be "cut off" from God. Baptism is a much more gender-inclusive sign, and it is also changes the sign to the new covenant - it is not just a renewal of the previous covenant - the Mosaic covenant was more elaborate and detailed in regard to laws than the Abrahamic covenant. Similarly, the new covenant was not simply a reiteration or renewal of the old covenant - it had some different laws in addition to the original ones.
We take note of this when Jesus and Paul explicitly reaffirm all of the Ten Commandments of Moses in one way or another, with one exception . . . the Sabbath commandment. The followers of Jesus were to observe a different day of worship, the Lord's Day, celebrating the resurrection of Jesus and the inauguration of the new covenant. This is why / how / when "the Sabbath" changed from Saturday to Sunday.
Jesus also added new requirements for his followers in the Sermon on the Mount: loving one's enemies, never retaliating, always forgiving. At the same time, Jesus declared all food clean and suitable for eating (Mark 7:15-20). In this case, Jesus did not reinstate the laws of clean and unclean found in the Old Testament. The new covenant was genuinely a new covenant.
The way ancient covenants work - only those portions of previous covenants that are reaffirmed continue to be binding on God's people in a new covenantal situation. Those portions that are annulled or not reaffirmed are not still binding on God's people. We need to remember that all covenants have laws and they are meant to be obeyed and obedience to God is not optional.