We are blessed to be living in an internet age. There are so many theological resources available to us! Many of these are free. Here are a few:
I really love Biblehub.com. On this one site you can read the Bible in any translation, or compare several translations at once. You can read commentaries for each and every verse in the Old Testament and in the New Testament. I especially like the commentaries from Matthew Henry, Barnes,' Notes, and Gill's Exposition. There are outlines and timelines.
There is a Lexicon in both Greek and Hebrew to look up any word. There are atlases and maps. There is a theological library, too, of works by early church fathers such as Ignatius, Irenaeus, Clement, Justin, Tertullian, Origen, and more. There are works by post-Nicene leaders such as Jerome and Augustine and lots more. All of Spurgeon's sermons are listed, as well as works by Bunyan, Flavel, Tozer, all of Isaac Watts' hymns, and much more. All for free.
Did you know of Charles Spurgeon's magnificent work of exposition of every line in every Psalm? It's a magnum opus called The Treasury of David. You can read it for free here at the Spurgeon Archive / Treasury of David.
The Treasury of David follows a consistent outline for each Psalm. Spurgeon introduces it. Then he presents a Division, or, an outline of progressive thought within the Psalm. Third, Spurgeon offers his exposition, almost always verse-by-verse. Fourth, Spurgeon gives some explanatory notes or Quaint Sayings. These enhance and fill out the exposition. Fifth, Spurgeon gives Hints to Preachers. And last, sometimes there are Additional Comments. It's a monumental contribution to the body of work around the Psalms. In fact, the series is still in print today. How blessed we are to be able to access this resource for free, online.
The Spurgeon site, maintained by Phil Johnson, also includes editions of Spurgeon's Sword & Trowel, Morning & Evening Devotionals, Spurgeon's Letters, and a biography by Fullerton.
Did you know that John MacArthur preached through the entire New Testament? He provides exposition for all the books and chapters of the New Testament, and many of the books in the Old. He also offers some topical sermons on issues of the day. There are nearly 4000 sermons at gty.org.
Some consider Dr Abner Chou one of the finest theologians working today. He is a professor at The Master's Seminary, and many of his lectures are available for free! They are here.
There are Bible Reading Plans galore to choose from:
Professor Horner's
Bible Gateway's varied selection
Ligonier's list of Bible reading Plans
Keep The Feast Challenge
Modern praise music reviews? Got 'em here! And here!
Need a Monster Cheat Sheet for John Owen’s Mortification of Sin in Believers?
What resources have you discovered that have helped you grow in knowledge and understanding in the Lord?