What is the consequence of mankind's fall into sin?

The consequence of mankind's fall into sin, as reflected in the Westminster Shorter Catechism, highlights the loss of communion with God and the exposure to misery. The fall represents a severing of the perfect relationship humanity originally enjoyed with God, resulting in spiritual death and alienation from the Creator.

This loss of communion manifests in various ways, notably including a separation from the divine presence and a state of sin and misery introduced into the world. The relationship that once promoted peace, joy, and fulfillment is degraded, leading to spiritual and moral decay. This condition also encompasses the broader scope of human suffering, reflecting the theological understanding that sin brings not just personal despair but also collective brokenness in society.

The other options do not align with the theological implications of the fall. A promise of eternal heaven is not a direct consequence of sin but rather a hope restored through redemption. Increased understanding of the universe does not emerge as a result of the fall; instead, the fall introduces confusion and misunderstanding about God's creation. Lastly, the notion of a guarantee of divine protection is contradicted by the experience of suffering and hardship resulting from sin. Thus, the correct answer encapsulates the significant and profound implications of humanity's fall into sin.