אֹהֵ֥ב כֶּ֙סֶף֙ לֹא־יִשְׂבַּ֣ע כֶּ֔סֶף וּמִֽי־אֹהֵ֥ב בֶּהָמ֖וֹן לֹ֣א תְבוּאָ֑ה גַּם־זֶ֖ה הָֽבֶל׃
He that loveth silver shall not be satisfied with silver; nor he that loveth abundance, with increase; this also is vanity.
Rashi on Ecclesiastes
He who loves money will never be satisfied with money. Whoever loves [to perform God’s] commandments never has his fill of them.12See the Gemara in Maseches Makkos 10a which interprets that this verse is referring to Moshe.