The prophet [Isaiah]... points out what will be the cause of this change; for he says that hatred, quarrel, and fighting will come to an end, because men will have a true knowledge of God. "They shall not hurt nor destroy in all my holy mountain: for the earth shall be full of the knowledge of the Lord, as the waters which cover the sea" (Isa. xi. ver. 9) Note it.
Ch.11 - Guide for the Perplexed (c. 1190) - Part III