What was the specific sin that caused the fall of our first parents?

The specific sin that caused the fall of our first parents, Adam and Eve, is identified as eating the forbidden fruit. In the Genesis account, God commanded Adam not to eat from the tree of the knowledge of good and evil, stating that doing so would lead to death. However, when Eve was tempted by the serpent, she chose to eat from the tree and then gave it to Adam, leading both to disobedience. This act of eating the fruit from the tree directly resulted in their fall and disobedience to God's command, thereby introducing sin into the world.

While refusing to follow God's commands, questioning His authority, and engaging with supernatural forces may also play a role in the broader narrative of temptation and sin, the act of eating the forbidden fruit is the specific action that represents their disobedience and leads to their separation from God. This highlights the significance of the choice to disobey God’s explicit instruction in the account of the fall.