What to read after Justification, Sanctification, and Union with Christ?

The opposition against legalism and Antinomianism is one fight that Calvin, the Westminster Divines, and Walter Marshall were involved in. Both errors are strongly connected, and we are prone to swing between these two errors. Each of them leads to the other. When we think that being forgiven in Christ means that we are not bound to the law, we fall into Antinomianism. As a reaction against Antinomianism, we can go to the other extreme, which is legalism. In legalism, we try to secure obedience by making it the condition for our salvation, and hence it becomes a heavy burden. The final result of this swinging is despair, which leads to hatred of the law and subsequently of God. The swinging between these two errors can only be broken by the gospel.