Though God's dealing with people have always been describable as "through grace", the period of the law is special. The giving of the ten commandments ushered in a unique time in which there were very negative consequences for not obeying God.
Before that, even during the 10 plagues RIGHT before the exodus and the giving of the ten commandments, God looked the other way when His people didn't trust Him. During the period under the law, from the 10 commandments to Christ on the cross proclaiming "It is finished" (the law is finished), God many times dealt very harshly with His people. In Abraham's and Job's time, (even Noah sleeping with his own daughter!) God forgave and more so. That is the agreement God has established with us today. The law has come and gone: Paul describes the law as "powerless" to make us holy. Christ has already made us holy.
We can never be more or less holy than right now. That is why we reminded to just "rest, stand, wait on God" and a host of other very passive statements. There are many statements of aggressiveness, but they relate to holding fast to our resting.
When we are told to not be unequally yoked, central to that idea, and the part that we share most with our daughters is that if one person sees that God has finished the work (which He has, at the cross) and your boyfriend doesn't believe that the law is finished, you will forever be frustrated and held back from the "more" that God has for you just so you can be with your future spouse emotionally and spiritually.
Live free in God's grace. It is the best and only real testimony we have. Our strongest guard is not to be at battle with ourselves to conquer whatever bad habit we may have. Our strongest guard should be against anyone who might strip away the freedom from condemnation before God we feel as we live in God's grace.
