There are two interpretations of this statement. Some take the words ‘cut off’ metaphorically and understand them to mean excommunication: ‘Paul wishes the Judaizers would excommunicate themselves.
Did Paul really wish evil on the Judaizers? Did he really wish to see them harm themselves? The purpose of this statement is not seriously to wish harm on the Judaizers, but to show what is the logical outcome of their emphasis on circumcision, and to demonstrate its foolishness. This statement is made in the hope that these false teachers will recoil from their madness. On another occasion, ‘I would to God that not only those but also all that hear me this day were both almost and altogether as I am’ (Acts 26:29). Paul expresses himself in this way for the sake of God’s people, not out of any personal malice. The gospel brings justice as well as grace, because those who reject it will face a severer judgment than if they had never heard it.