As well as reading the above mentioned works you should definitely read his "Postils". These sermons are quite brilliant, and reveal Luther as the warm and tender hearted Pastor that he was!

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Satch, Particular Baptist, England
"If ye then be risen with Christ, seek those things which are above, where Christ sitteth on the right hand of God." Colossians 3.1
http://www.book-academy.co.uk For FREE downloadable pdf commentaries recommended by C.H. Spurgeon, Spurgeon's works, and Great Puritan works.
ECCLESIA REFORMATA ET SEMPER REFORMANDA