For Lorenzo Valla, in De libero arbitrio, divine Providence seems to dispel the freedom of human will. We are therefore confronted with the dilemma that has its origins in ancient times and lives on in the theology of the Middle Ages. It introduced the interference of divine Providence into the realm of human responsibility. However, the author considers that the will of God, sustained by his wisdom, cannot but act in the right way dispensing justice and goodness. It is true that the decisions of divine Providence are not accessible to mankind. But it is precisely for this reason that the rational attempt to penetrate them through the doctrine of original sin leads to inevitable contradictions. Sentencing Adam and his descendants was in fact an act of free will on the part of the Divinity. God chose this condemnation rather than divine mercy; there is therefore no need for God to change our nature and substance. Man continues to sin in spite of the grace given by Christ and thus, like Adam, is endowed with free will.
Keywords: Free will of man, impenetrability of God, original sin