Before you begin reading his commentaries, it would be helpful to know how Aquinas understands and interprets Scripture. I suggest the following articles:
Here are his commentaries:
- Catena Aurea (an arrangement of quotations from the early Church fathers into a verse-by-verse commentary on the Gospels): Matthew, Mark, Luke, John
- Psalms (also here)
- Job (also here as a Word doc)
- Gospel of John
- First Corinthians (also here)
- Second Corinthians (also here)
- Ephesians (also here)
- Colossians (also here)
- Hebrews (also here: Part 1 and Part 2)
- 1 Thessalonians
Also see the Index of Scripture References in the Summa Theologiae for a good indication of how he understands many, MANY other passages from the Bible.
St. Thomas Aquinas, Angelic Doctor and the Church's greatest theologian ... pray for us.