Antinomianism is a lawlessness which is found in which faith baptizes the Christian life and no need is found for living rightly. There is a certain truth to Antinomianism in that we are saved only by Christ's work alone and not works.
You see however that the faith that justifies is never alone. Jesus' followers will be "known by their fruit." There is a sort of cheapness to Antinomianism which suggests that one has never really met or loved God.
An interesting form of Antinomianism is Legalism. Legalism expects perfection in life and multiplies rules in great excess. It looks the exact opposite of Antinomianism but it is another form of it.
You see it works like this. Living rightly is based on the way God says not on the way man says.
God says a great many things to mankind and a great deal of rules and principles to his children. But you see the specifics are left blank. We are God's children and he wants us in faith to figure out the details for ourselves.
A great many earthly parents alienate their children by trying to figure out the details of their children’s lives for them. The should often be happy their children wish to live peaceably and do this or that meaningful thing but they instead are upset that their children has chosen "this occupation" or won’t do "that" which is a small thing.
You see our heavenly father is a good father and lets us work out the details. He has commanded us to show love to our brother but has given us liberty to figure out how we should show love to our brother in this world.
Legalism takes away human liberty and is thus opposed to the will of God. It spells out parts of the law in ways God never intended. It attempts to take away human freedom on how to show love or do well.
You see since legalism moves from the personal preference of live and impose itself on others it is sin and lawlessness because it imposes an order in the world that was never meant to be.
You see too creating and teaching many rules is just as sinful and rebellious against God and ignoring all the rules. Because right living is of course based on living as God intends.
Augustine once said "love God and do what you please." This is the spirit of the bible. Of course we need to truly seek to learn from the bible what love is.
Sometimes love is unexpected and what is not loving is also unexpected. We need the structure of love to come from God but the details are left to us. The details cannot come from the church or authority.
You see it is not bad for the church to suggest details of right living in areas which are not spelled out but to absolutize them is the sin. Because the children of God are free to work many not spelled out details out for themselves.