Midrash su Salmi 139:17

But when David learned Torah and grew great (in it), what did he say? (Psalms 139:17) "And to me, how precious are Your loved ones (i.e., Torah scholars), O G-d! How mighty is their sum!" And (Ibid. 119:72) "Better to me is the Torah of Your mouth than thousands of gold and silver." For gold and silver take a man out of this world and the next, but Torah brings a man to life in the world to come.