Ad Beatissimi Apostolorum §14

¹⁴ But there is still, Venerable Brethren, a deeper root of the evils we have hitherto been deploring, and unless the efforts of good men concentrate on its extirpation, that tranquil stability and peacefulness of human relations we so much desire, can never be attained. The apostle himself tells us what it is: "The desire of money is the root of all evils" (I. Tim vi. 10). If any one considers the evils under which human society is at present labouring, they will all be seen to spring from this root.