Examples:

• To measure happiness by the absence of sorrow and misery in this world is to turn one's back on the Gospel.
• No one has a monopoly on truth; indeed, to believe that is to turn one's back on truth.
• This is to turn one's back on someone who has provided us with the main theoretical and programmatic approach, the only one that has survived within the field of Marxism (who nowadays defends Stalinism?).