Bede

He who thinks evil with astonished eyes, etc. It is more grievous to accomplish evil than to do it. Not only does he accomplish evil who acts perversely and harmfully with the members of his body, but also he who with fixed intention plans to commit it. For the proud, indignant, are accustomed to bite their lips, and to have astonished eyes, and not to see the present, who for some time silently ponder with diligent mind. …

Commentary on Proverbs ↗