The connection between joy and the commandments is counter-intuitive to many people in modern culture. And yet that connection is laid out plainly in the Scriptures. The very first Psalm describes the just man as one to whom God’s law is delightful: “the law of the Lord is his joy he finds pleasure in the Law of God” (Psalm 1:2). Not his “obligation,” but his joy. Christ Himself reaffirms this connection for His disciples: “If you keep my commandments, you will remain in my love, just as I have kept my Father’s commandments and remain in his love. I have told you this so that my joy may be in you and your joy may be complete” (John 15:10-11). Why is the commandment of the Lord a source of joy? Because joy comes from fulfilling our design, and God’s commandment reveals our design.
When my children were somewhere between one and two years old, they all developed a taste for the woodchips that cover the ground at most of the local playgrounds. Whenever I caught them putting a woodchip in their mouth, I take it away and say, “Don’t eat that.” That’s my law: don’t eat woodchips. Of course, they didn’t get it, and thought I was being mean. But that’s just because they didn’t understand their own internal structure as well as I do. I knew they would get more pleasure, more delight, from not choking to death or trying to digest a massive splinter. And my law, even if they didn’t’ realize it, expressed the way they are made and the way to be happy. So it’s no surprise to me that God’s first law to His children in the Garden of Eden was, “Don’t eat that; it could kill you.” And it’s no surprise that they didn’t understand, and disobeyed, and that the disobedience made them miserable. Because there’s an intrinsic relationship between a) God’s commandments; b) human design; and c) joy.
Let me give one more example: The Church, reflecting on the nature of human sexuality, understands that our design is such that marriage, sex and babies must go together and in that order. Furthermore, the sexual union of the spouses and their fertility must not be ripped apart. The self-gift of sexuality will be distorted and frustrated if we deliberately do something to rip fertility out of the act. This is a truth of our design, and it can be expressed in a commandment: contraception is immoral. Not owing to my own intelligence or virtue, but thanks to a good friend who gave me a book on the Churches teaching on Marriage and contraception, and because I have faith in Christ and His Church, we never used contraception in our marriage. And I can honestly say that my kids have probably given me as much joy as anything else in my life. Which means that now, I don’t just understand or obey the commandment – I rejoice in it. The Church’s law on contraception has been a source of joy. Again, the main point: God’s commandment expresses our design, and acting according to our design gives lasting, permanent joy.
The goal isn’t just to experience joy as an outcome of following God’s law, but to experience joy in the process of following God’s law. And the only way that happens is when you have virtue. Consider an example of growing in excellence and delight precisely by being docile to instructions that may not seem to make much sense at first: learning to play piano. When you start to take piano lessons, the whole thing feels artificial and restrictive. You have to hold your hands a certain way, repeat unpleasant-sounding scales over and over, learn how to correlate little black dots with letters with the keys, etc... None of it feels related to what you want to do on the piano, which is just play music you like. But if you stick with it, if you submit to “the rules” of music and piano training, one day you might wake up and find yourself an artist.