But not according to knowledge ...
Brothers, my heart's desire and prayer to God for them is that they may be saved. For I bear them witness that they have a zeal for God, but not according to knowledge. For, being ignorant of the righteousness of God, and seeking to establish their own, they did not submit to God's righteousness. For Christ is the end of the law for righteousness to everyone who believes. -Romans 10:1-4 NLT
The world is full of religious zealots. In 2001 Islamic zealots flew planes into buildings and killed many innocent people. These had a perverted and ignorant zeal for God. These were blinded by hate and did not have a knowledge of the love of God. In some sense all fleshly zeal is bereft of any sort of love or compassion. Such zeal is filled with pride and totally bankrupt of any sort of righteous humility. As Paul says here, such zeal seeks to establish its own righteousness.
What do you think the apostle means when he states that "Christ is the end of the law for righteousness". Theologian Adam Clarke writes "Where the law ends, Christ begins." I love that! One will not be made righteous in Christ if they seek to be right with God by hanging on to external laws, principles and rules. For what the law does for the head Christ does for the heart. Following the law has the ability to change our head but following Christ changes our heart.
Teach us Lord that we may have a zeal for you that is in accordance with your love and your compassion.