Bernardus Parmensis (ca. 1250), Glossa ordinaria to X 3.1.2 s.v. Clerici arma:  "Clerici arma portare non debent, xxiii. questione ultima, Clerici et c. Quicumque (C.23 q.8 c.5 and c.6) sine iusta causa.  Iustam causam intellige si per loca periculosa transitum faciunt tunc possunt portare arma ad terrorem latronum,  licet percutere non debeant (Clerics ought not to bear arms .  .  . without a just reason.  You may understand just reason if they travel through dangerous territories then they may bear arms to strike fear into robbers, although they ought not to strike)

Hostiensis (ca. 1270) Commentary to X 3.1.2 s.v. Clerici arma:  "Quod intelligas ad impugnandum; nam ex causa arma defensionis possunt portare .  .  . sed et laicis hoc interdictum est, ut Cod. 11.47(46).1 .  .  . necessitate tamen iminente sufficit .  .  . (Which you should understand to mean "attacking."  For clerics can bear arms for reason of defense .  .  . even lay persons are forbidden to bear arms as in the Codex .  .  . <but> reason of great necessity <they can> .  .  . )