Summa theologiae IIaIIae 10: On relations with unbelievers

articulus 8: Whether unbelievers ought to be coerced into the faith

It seems that unbelievers ought by no means to be coerced into the faith.

obiectio 1: For it is said at Matthew 13:28f that the servants of the householder in whose field tares had been sown asked him: ‘Wilt thou then that we go and gather them up?’ And he replied: ‘Nay, lest while ye gather up the tares, ye root up also the wheat with them.’ Commenting on this, Chrysostom says: ‘The Lord speaks thus in order to prevent the slaying of men. For it is not right to slay heretics, because if you kill them you will necessarily destroy many holy persons also.’ For the same reason, therefore, it seems that unbelievers ought not to be coerced into the faith.

obiectio 2: Moreover, it is said in the Decretum: ‘Concerning the Jews, the holy synod prescribes that henceforth none are to be brought to believe by force.’ Nor, therefore, for the same reason, ought other unbelievers to be coerced into the faith.

obiectio 3: Moreover, Augustine says that although a man can do many things unwillingly, ‘he cannot believe unless he is willing’. But the will cannot be compelled. Therefore it seems that unbelievers ought not to be coerced into the faith.

obiectio 4: Moreover, it is said at Ezekiel 18:32, as though God were speaking: ‘I desire not the death of the sinner.’ But we ought to conform our will to the Divine will, as stated above. Therefore again we should not desire unbelievers to be slain.