I discovered something else that will warm your heart!
Actually, the legalist and the true convert actually do the same works of the Law, but for entirely different motives. Being converted to Christ does not mean that we escape from the obligation to follow God's moral Law. It is the Mosaic ceremonial Law that we leave behind.
The legalist follows the moral Law to escape judgment, punishment and hell. He follows it in order to be saved. He does it for entirely selfish reasons, not for God's glory or for the good of all. It is a burdensome duty for him, but he does not have personal happiness if he cannot follow it perfectly.
The true convert receives salvation by faith, but then follows the exact same moral Law, but to glorify Christ and for the good of all others. He follows the Law and does exactly the same works of the Law as the legalist, but because he loves God, knows that he is saved by grace, and loves to do what he can to follow the commandments of Christ because it is good in itself to follow them. Salvation by faith brings peace to him, and following the commandments brings happiness, especially when he sees that Christ is glorified and others are benefiting from it.