To be relevant, all theology must relate to context. This study is an example of the complexities encountered in the actual practice of contextualization. It examines the notion of "sin" in the Kongo culture and evaluates it through the lens of the Old Testament understanding of sin. In the Kongo context, sin is understood as any act that breaks the harmony of the community, allowing any kind of evil to enter it. This understanding can be nuanced by comparison with the biblical view of sin as always being committed before God, the creator of the world and the one to whom all human beings owe their life. The rich imagery for sin in the Old Testament cannot be captured by the one Kongo word disumu; a wider vocabulary can and must be developed.