Since I’m a fan of commentaries and they are a staple in my book collection I was glad to read this:

When the wonder of the gospel breaks into your life, you feel as though you are the first person to discover its power and glory. Where has Christ been hidden all these years? He seems so fresh,
so new, so full of grace. Then comes a second discovery—it is you who have been blind, but now you have experienced exactly the same as countless others before you. You compare notes. Sure enough, you are not the first! Thankfully you will not be the last.

Discovering a Key

If my own experience is anything by which to judge, discovering Romans can be a similar experience.

I still remember, as a Christian teenager, the slow dawning of this thought in my mind: all Scripture is God-breathed and useful to me, but it also seems to have a shape and structure, a center and circumference. If that is so, then some biblical books may be foundational; these should be mastered first.

Then came the realization that (alongside systematic theologies) biblical commentaries must be the foundation of my book collection.

–In Christ Alone, by Sinclair B. Ferguson