Jeremiah 2:19
Thine own wickedness shall correct thee, and thy backslidings shall reprove thee: know therefore and see that it is an evil thing and bitter, that thou hast forsaken the LORD thy God, and that my fear is not in thee, saith the Lord GOD of hosts.
Thine own wickedness corrects the wrongdoer, and backslidings reprove the backslider, so that discipline comes through the consequences of one's own wrong course. To forsake the Lord God and to be without reverent fear of Him is an evil thing and bitter. Even chosen status and special advantages did not keep Israel faithful, and departure from God proved the people were not the light of the world.
The same warning reaches all who profess to belong to God yet turn from Him to false worship and to broken sources that cannot give life, and such choices bring bondage and loss. Forsaking God in this sense includes laying aside His Word and making human writings the chief source of instruction.