The hypocritical accusers pretend to entrust the judgement to him whereas it is actually he himself whom they wish to accuse and judge. Jesus, on the other hand, is "full of grace and truth" (Jn 1: 14): he can read every human heart, he wants to condemn the sin but save the sinner, and unmask hypocrisy. St John the Evangelist highlights one detail: while his accusers are insistently interrogating him, Jesus bends down and starts writing with his finger on the ground. St Augustine notes that this gesture portrays Christ as the divine legislator: in fact, God wrote the law with his finger on tablets of stone (cf. Commentary on John's Gospel, 33,5). Thus Jesus is the Legislator, he is Justice in person. And what is his sentence? "Let him who is without sin among you be the first to throw a stone at her". These words are full of the disarming power of truth that pulls down the wall of hypocrisy.

[Pope Benedict, Angelus 21 March 2010]