Full Idea
In order to have the right to punish the guilty, we ought first of all to purify ourselves of their crimes. …But once this is accomplished we shall no longer feel the least desire to punish, or as little as possible and with extreme sorrow.
Gist of Idea
To punish people we must ourselves be innocent - but that undermines the desire to punish
Source
Simone Weil (The Need for Roots [1943], III 'Growing')
Book Reference
Weil,Simone: 'The Need for Roots' [Routledge 2002], p.238
A Reaction
Elsewhere she endorses punishment, as a social necessity, and a redemption for the wicked. This idea looks like a bit of a change of heart. She may be thinking of Jesus on the mote in someone's eye.