Christian commentators generally understand this statement as referring to humanity's newly acquired knowledge of evil through personal experience. Before the Fall, Adam and Eve knew the goodness of God and His creation. Through disobedience, they encountered guilt, shame, and the painful consequences of evil firsthand.
Some interpreters emphasize that humanity had attempted to claim the authority to determine good and evil independently of God. The serpent had promised godlike wisdom, but the result was not divine perfection. Instead, humanity discovered its own weakness and vulnerability.
Others see an element of solemn irony in God's words. Adam and Eve had sought to become like God, but their rebellion had brought them into a condition far removed from the life they previously enjoyed.
God then prevented them from eating from the tree of life. This action is often understood as a judgment that also contained mercy, preventing fallen humanity from remaining indefinitely in its corrupted condition.