“The Lord was pleased, for his righteousness’ sake, to magnify his law and make it glorious.” (Isaiah 42:21).

1. God’s righteousness inclines him to make his own instruction great and glorious. “For his righteousness’ sake he magnifies and glorifies his instruction.”
2. So we learn something crucial about divine righteousness. It is the consistent and compelling inclination to do what is right, which in God’s case is defined by his own infinite worth. No one outside God dictates what is right for him. What is right for God is what agrees with his infinite greatness and infinite value. Therefore, it is right (righteous) that his perfect instruction be magnified and glorified.
3. We also learn something about unrighteousness. It would be unrighteous of God to act in a way that diminishes his glory. If he made little of his instruction or failed to magnify it and glorify it, he would be unrighteous. He would be acting as if some instruction were greater than his. That would be false, and God would be a liar. That is what unrighteousness is: Acting a lie. Acting as if God were not infinitely great and glorious and valuable.
4. God loves to make his instruction great and glorious. He delights in it. It pleases him to make his instruction great and glorious. “The Lord was pleased to magnify his law and make it glorious.” He is not acting against his deepest desire, but in accord with it when he magnifies the value of his own word.
5. Thus God acts in freedom. Freedom is doing what one delights to do, and delighting to do what is right. Thus God does what is right and he delights to do it. He is free.
6. God’s nature is such that joy and righteousness are mutually defining. At his essence God is actively, infinitely delighting. And since what he has eternally delighted in is his own perfections standing forth in the Son, this delight is right. It is infinitely righteous. It is right that God delight infinitely in what is infinitely delightful. Therefore God’s being joyful and God’s being righteous are two ways of describing the same reality. He delights to do things because they are righteous. And he does righteous things because he delights to. “I practice righteousness. For in this I delight, declares the Lord” (Jeremiah 9:24).
7. Therefore, the biblical call for us to rejoice in the Lord and to practice righteousness is ultimately one united call. It is rooted in who God is. We have been redeemed by Christ to be conformed to God — that is, to become creatures whose identity is most fundamentally righteous joy and joyful righteousness. We will in the end be perfectly free — doing what we delight to do, and delighting in what is right. We will join him from the heart and “for his righteousness' sake, magnify his law and make it glorious.”