וַיִּשְׁמַ֤ן יְשֻׁרוּן֙ וַיִּבְעָ֔ט שָׁמַ֖נְתָּ עָבִ֣יתָ כָּשִׂ֑יתָ וַיִּטֹּשׁ֙ אֱל֣וֹהַ עָשָׂ֔הוּ וַיְנַבֵּ֖ל צ֥וּר יְשֻׁעָתֽוֹ׃
But Jeshurun waxed fat, and kicked— Thou didst wax fat, thou didst grow thick, thou didst become gross— And he forsook God who made him, And contemned the Rock of his salvation.
Read Jewish philosophical commentary on Deuteronomy 32:15: and classical philosophical sources.