How does Aquinas engage justification in the Summa?

Leonardo De Chirico is the pastor of Breccia di Roma, a church that he helped plant in Rome in 2009, and Vice Chairman of the Italian Evangelical Alliance. Previously, Leonardo planted and pastored an evangelical church in Ferrara, Italy from 1997 to 2009. He earned degrees in history (University of Bologna), theology (ETCW, Bridgend, Wales) and bioethics (University of Padova). Here, Leonardo answers questions from the talk "Did Thomas Aquinas Teach Justification by Faith?", given at the 2023 European Leadership Forum.