Why did Peter Abelard believe that intention mattered more than actions in judging sin?

In his work Ethica (or Scito te ipsum), Peter Abelard argued that human actions themselves are neither good nor bad in the sight of God, and therefore do not inherently make a person better or worse.1

Instead, Abelard maintained that sin is not an external act or a physical deed; rather, it is uniquely defined by the consent of the human mind to what it knows to be wrong. By focusing on intention, Abelard sought to address the moral problem of holding individuals responsible for the mere existence of physical desires, which are often involuntary. For example, he argued that the sin of sexual wrongdoing lies not in the act itself, nor even in the desire for it, but specifically in mentally consenting to that desire. This emphasis on internal consent over external behavior marked a significant shift in medieval ethical thought, distinguishing his views from those who equated the mere presence of wrong desires with the commission of a sinful act.21