Sin plays a large role over the first three chapters. To understand the concept of grace, we must first get to grips with sin. Here, the big picture story is told of God’s wrath in response to our deliberate “turning away from God”. God’s wrath culminates in the “giv[ing] them over to sinful desires of their hearts”. Although God is both slow and reluctant to execute his wrath, we see it here in the early part of Romans in order to best understand the arguments made later epistle for the greatness of his grace; “it serves as the background to his ‘proper work’ of mercy”.1
From verses 18 to 31, the story depicts a commonly accepted view of the world to the Jewish audience, often as propaganda against the pagan world. However, Paul condemns those who wish to cast judgement on the pagan world, stating they are also worthy of judgement. God does not show partiality in grace, nor in wrath. We are all under God, and to cast judgement on others is futile, for we are all deserving of condemnation.