Glossa Ordinaria — as excerpted in the Catena Aurea on Mark 13:9-13

“(non occ.) Another anxiety might also arise in the breasts of the disciples. Lest therefore after hearing that they were to be brought before kings and rulers, they should fear that their want of science and eloquence should render them unable to answer, our Lord consoles them by saying, But when they shall lead you and deliver you up, take no thought beforehand what ye shall speak, but whatsoever shall be given you in that hour, that speak ye.”