Living in the United States in the 21st century, we are blessed with a plethora of theological resources. The Bible, the gospel, and the things of God have never been so accessible as they are now in our society. Below are some of the books that have been most helpful for my understanding of salvation, which is the subject of Article IV of The Baptist Faith and Message.
Conversion by Michael Lawrence
Faith Alone by Thomas R. Schreiner
Finally Alive by John Piper (available as a free PDF download online)
It Is Well: Expositions on Substitutionary Atonement by Mark Dever and Michael Lawrence
Redemption Accomplished and Applied by John Murray
What Is the Gospel? by Greg Gilbert