For those with ears to hear!
Saul (aka Paul) was a culture warrior before he met the risen Christ on the Damacus Rd. He believed it his religious duty to persecute those Jews who were doing it wrong (those pesky Jews who believed in Jesus). Michael Gorman tells us how and how the Christian Paul was transformed.
“He was most likely attempting to secure his justification before God through imitating, at least to some degree, the violent priestly hero Phinehas, who purified Israel and stayed God’s wrath by killing an Israelite and his Midianite consort (Num. 25: 6-13). According to Psalm 106:31 (LXX 105:31), Phinehas was justified by his violent zeal: his act was “reckoned to him as righteousness” (elogisthē autō eis dikaiosynēn); the Greek phrase is exactly the same as the parallel text in Genesis 15:6 and in Romans 4:3, 5, 9, 22-24. When Paul was justified, reconciled to God, his oppressive, violent public behavior changed dramatically, and so did his spirituality, his relationship to God. In fact, the two changed simultaneously, and in tandem. Paul no longer sought justification in his misguided (as he later saw it) zeal for God that resulted in hatred for, exclusion of, and mistreatment of others. He would later describe his previous zealous, violent behavior as one of the manifestations of sin and adikia that generated the need for reconciliation/ justification (Rom. 3:9-18). Paul’s own life-story confirms that justification has a public, observable, social face: it includes the just practices of non-retaliation/ non-retaliation/ nonviolence (1 Cor. 4:11-13) and reconciliation (cf. 2 Cor. 5:18-20), as well as commitment to the poor (e.g., Gal. 2:10 and the Jerusalem collection). In other words, to be justified is to be missionally rearranged and redirected.”
(Gorman, Michael J.. Becoming the Gospel: Paul, Participation, and Mission (The Gospel and Our Culture Series (GOCS)) (Kindle Locations 5948-5950). Wm. B. Eerdmans Publishing Co.. Kindle Edition.)