God now confronts its with the revelation of His law. We can respond to the law in order to gain merit, to seek justification before God by doing the best we can to conform. But strict adherence to the law does not mean that we are legalists. A person who never misses a Sabbath school or a prayer meeting is not necessarily a legalist. Only when obedience is done to gain advantage or merit with God are we legalists.
Legalism has a deadly effect upon the human spirit.
It involves us in a preoccupation with our own moral balance sheet. It amounts to a competition for virtue. The mask of virtue can provide the perfect disguise for the most unlovely motives. It often leads to seeking satisfaction through it personal advantage over someone else by means of religion. It lacks compassion.