I find it a little bit irritating that after nearly two thousand years, there are still people in the Church who believe Christians are supposed to obey some or all of the 613 laws of the Jews. However, the purpose of the Old Testament Law was to convict people of their inability to keep the law, and to point us to our need for Jesus Christ as Savior. The Apostle Paul wrote, "Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith. But after that faith is come, we are no longer under a schoolmaster" (Gal. 3:24-25). Jesus did not come to destroy the Law, but He did come to fulfill (complete) it (Matt. 5:17). The Greek word translated "fulfil" in the KJV is πληρόω (plēroō) which means "to render full," i.e. "to complete." Because none of us is capable of obeying the Law, Jesus obeyed it for us; His death paid our penalty, and His Resurrection provided us with righteousness (which is defined as the total fulfillment of the Law - Rom. 5:21; 1 Cor. 15:3-4).
Paul, speaking to genuine Christians, wrote, "O foolish Galatians, who hath bewitched you that ye should not obey the truth, before whose eyes Jesus Christ hath been evidently set forth, crucified among you? This only would I learn of you, received ye the Spirit by the works of the law, or by the hearing of faith? Are ye so foolish, having begun in the Spirit, are ye now made perfect by the flesh?" (Gal. 3:1-3). We were born again by faith in the death, burial, and resurrection of Jesus on our behalf. We no longer are under the Law, but are to live in the Spirit (Gal. 5:25).
There are those who would demand we obey all 613 Old Testament laws, and there are others who would pick and choose which of that number still apply. These tend to divide God's Law: the moral law found in the Ten Commandments, and the ceremonial law consisting of hundreds of statutes and ordinances. Jesus said that all of the Law was fulfilled in these two: "And thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind, and with all thy strength: this is the first commandment. And the second is like, namely this, thou shalt love thy neighbour as thyself. There is none other commandment greater than these" (Mk. 12:30-31).
Paul, apparently believing man is incapable of loving his neighbor without his love for God motivating him, simplified it even more: "For all the law is fulfilled in one word, even in this; thou shalt love thy neighbour as thyself" (Gal. 5:14). If we are truly grateful for what Jesus has done for us, we will want to please Him by doing those things which bless others (1 Jn. 3:16-18). We will give to the poor; we will give cheerfully and according to our conscience to the Church so that it can spread the Good News (2 Cor. 9:7); we will be hospitable to others, etc.; because that is what we want others to do for us. Our love of God is expressed in our love for others.