Who said "Guilt is a prison of one's own making"?

This quote is attributed to Armstrong.

Guilt is a prison of one's own making - Armstrong

"Guilt is a prison of one's own making"

Armstrong Truth

Character in And Then There Were None

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"We are none of us infallible."

"The innocent suffer with the guilty."

"Each of us has something to hide."

"We deserve what comes."

"Lucy, you got some 'splainin' to do!"

"You must always be honest with the people you love."

"Truth always comes out in the end."

"Honesty is always the best policy."