Your friend saw this resource on bethinking.org and thought you should see it:
Are we sinners?
What does human society tell us about human nature? Are we essentially good or bad?
See the full resource online by visiting bethinking.org:
https://www.bethinking.org/christian-beliefs/are-we-sinners
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bethinking.org is a collection of resources which aims to make sense of the big questions of life about God, Jesus and Christianity.