Historical-critical exegesis of the parable of the Laborers in the Vineyard (Matt 20:1–16) has yielded multiple, often mutually exclusive interpretations. This variety and conflict generally can be traced to more-or-less evident “optics” that inform the exegete’s hermeneutical perspective, for example, existentialist, psychological, socioeconomic, and theological. Among the last, sola fide has been especially prominent in guiding readings of the parable in terms of grace and merit. But does this optic do justice to the parable, and is it theologically coherent? In this article, I pursue these questions by considering Thomas Aquinas’s discussion of the parable, in conjunction with his reflections on merit and grace. Materially, I hope to show the utility of Thomas’s thought for illuminating the relationship between God’s grace and human merit in salvation history. As he interprets it, the Late-come Workers is not about the conflict between unearned grace and merited reward. Instead, it is evidence of how justice and mercy, present in all of God’s acts, are visible in the work of salvation. Formally, I want to draw out some of the abiding value of Thomas’s method of exegesis, which commends itself, in part, because it combines speculative skill with a thorough knowledge of Scripture, allowing St. Thomas to address the richness of the text more fully and coherently than a number of contemporary accounts. Yet, Thomas’s method need not be viewed as locked into a zero-sum game with these approaches; rather, his exegesis is expansive enough to integrate a great deal of historical-critical findings.