In the lips of the wise is found wisdom, etc. The rod on the back is vengeance on the posterior, that is, in the following life; well expressed by that famous plague by which the Philistines were struck on their buttocks (1 Sam. V). Therefore, whoever does not want to carry the rod on their back, let them carry wisdom in their lips. I will speak the praises of Christ and preach His commandments. However, because it is always suitable to praise God but not always to teach, it is fitting that the wise do not teach everything they know to everyone, rightly adding:
[AD 735] Bede on Proverbs 10:13