Many scholars have noted similarities between the discussions of idolatry and resulting sinfulness in Wis 13:1–14:31 and Rom 1:18–32. Several scholars have also noted where Paul differs from his alleged source and have offered general explanations for this disagreement. My paper advances this conversation by providing a detailed study of specific passages in Wisdom of Solomon and Romans that discuss the idea that idolatry leads to further sin in an attempt to discern the particular reason(s) both authors make this argument. I then show how each author’s reasoning contributes to their larger discussion (theology) of sin in their respective works. Finally, I compare and contrast both the details of their arguments and their overall understandings of sin in order to better understand how and why their theology cohered and differed. The result of such analysis is a deeper understanding of the theology of Wisdom and Romans with reference to sin, and a deeper understanding of how Paul reasoned to his theological conclusions. These findings also shed further light on how much Paul agreed with Wisdom’s treatment of sin; and if, how much, and why Paul differed. This paper expands the work of Jonathan Linebaugh, God, Grace, and Righteousness in Wisdom of Solomon and Paul’s Letter to the Romans: Texts in Conversation, by focusing on the details of select passages related to a single idea and examining the author’s thinking about this idea.