If studying systematic theology is brand new to you, or you just want a better grasp on some of the concepts in these introductory posts, let me recommend 2 books:
First, Faithful Theology: An Introduction by Graham Cole. I love this entire series of books, and so you’ll see them recommended (and footnoted) often. This one explains how to do theology well, what categories to think through, and what errors to avoid.
The second is Sound Doctrine by Bobby Jamieson. This one isn’t so much about how to do theology, but why you should do theology and what role it plays in the local church. It’s a little bit easier to read than the first (though that one isn’t difficult), and pretty short too.
In the individual posts themselves, I have links and footnotes to larger resources, but I wanted to give you these suggestions in case you want something a bit more entry-level to take up and read for yourself.