Here are more sermons on the importance of preaching the law:
Why Preach the Law So Strictly? by Rev. Foppe VanderZwaag [ Text: Matthew 6:21 (Audio)]
Why Preach the Law? by Rev. Pieter VanderMeyden [Text: Romans 7:1-25 (Audio)]
Preach the Law to Get to the Gospel, by Rev. Ian Goligher [Text: Mark 12:28-34 (Audio)]
