Roger, I should stop getting into these types of discussions. I don’t think they have much to do with science, and especially not with evolutionary science. But, I believe some of your assumptions are wrong. In the first place, some gentiles did participate in the Jewish covenant… we have Rahab and Ruth for example. But we also have specific commands related to participation of other peoples in Hebrew covenant (Exodus 12:48). We know that even Nebuchadnezer was subject to God, and could participate in God’s grace, even though he was from a pagan nation. While the old covenant was primarily with Israel, there are enough exceptions described in the old testament to indicate that God’s covenant of love was bigger than just this people. This became very evident at Pentecost, and later in visions to Peter. Scripture helps us to understand the ceremonial laws of the old covenant, vs the laws that continued to apply to our daily lives after Jesus came. If you don’t like the word “law”, you can change it to “commands”.
Paul did not forbid gentiles to be circumcised (he circumcised Timothy), but he was angry with those who said it was a requirement.
Gentiles were under the old covenant too, but they just didn’t know it. But they were rejected under the conditions of the old covenant, except for those who accepted the conditions. But even there, for the Israelites, merely accepting the outward constraints of the old covenant did not mean a true communion with God, if their hearts were not desiring to serve and love God. This included even in the old testament, to look after the poor and widows and orphans. (Micah 6:6-8, Deuternonomy 14:29, Isaiah 10:2, Malachi 3:5)
This was also Jesus message, to care for the poor and orphans. James 1:27. And to keep ourselves unpolluted from the world.
And I agree that Jesus did not cancel the old covenant, but fulfilled it.
Do we have to keep the ten commandments? I don’t think the number 10 is the issue. But we know we should love God. We should love our neighbor. We know we should not make any idols of anything or worship anything other than the true God. We should not make images of God because that dishonors and diminishes God. We should honor God’s name. We should repect and honor parents (and care for them). We should not steal. We should honor the sabbath rest. We should not lie against others. We should not murder (nor cause others harm). We should not covet what others have, nor resent them having it. We should not be adulterous, nor desire someone else’s wife or husband (nor rape someone, nor live in sexual immorality, incl homosex). When we do any of these things, God is displeased. When we live in these things, we deny God, and we say that we do not really love God. When we confess and repent, God is gracious to forgive us our sins, based on the blood and sacrifice of his son Jesus (God in the flesh). We should have love, joy, peace, forbearance, kindness, goodness, faithfulness, gentleness and self-control. We should teach these things to our children. When God’s spirit lives in us, in our hearts, in our lives, then we will desire to be an overcomer. Then our individual struggle will be victorious in Christ. Then we will no longer be a slave to sin, but a slave to Christ. Then these commands will no longer be burdensome, but will be a new natural outcome of our relationship with God. We will be a born again new creation!