If you are seeking the true Christ, read these sermons. MacDonald wrote as one filled with the Spirit; with the motive/desire to remove the yoke of man's made religion while pointing to the truth of the risen Lord. My life has been changed, in part due to MacDonald's obedience to write the truth in the Spirit.
His writing style is deep and thoughtful, and always well worth reading and re-reading until the truth of what he is saying sinks in. I would also highly recommend his fictional works-especially those written for children. He was the original JRR Tolkien (Tolkien and CS Lewis were both greatly influenced by him both in style and faith), so if you enjoyed the Lord of the Rings, you will find more to enjoy in MacDonald's fiction.