Here are some wonderful links to some good resources

http://www.reformed.org/books/institutes/ – Calvin’s Institues of the Christian Religion

http://www.spurgeon.org/treasury/treasury.htm – Spurgeon’s Treasury of David

http://www.ccel.org/c/calvin/comment3/comm_index.htm – John Calvin’s Complete Commentary of the Bible

http://www.ccel.org/ccel/owen/mort.pdf – John Owen’s Of the Mortification of Sin in the Believer

http://www.jonathanedwards.com/sermons/Warnings/sinners.htm – Jonathon Edward’s Sinners in the Hands of an Angry God

http://www.pbministries.org/books/pink/pinks_archive.htm – Writings of AW Pink

http://www.pbministries.org/books/gill/gills_archive.htm – Writings of John Gill