In 1 Corinthians 10:23, most English translations use quotation marks to suggest that Paul is quoting someone else. For instance, the RSV says...
“All things are lawful,” but not all things are helpful.
“All things are lawful,” but not all things build up.
Koine Greek sources do not have quotation marks, so this is a translational assumption. On what basis is that assumption made?
Is there anything in the source grammar or the immediate textual context that suggests Paul is saying “Some people say 'All things are lawful', but I say...” or “You might say... but I say...”?
What rules out the interpretation that Paul is agreeing with both points of view, i.e. “It is true that all things are lawful, but also that not all things are helpful.”
I have read the comments on Quotations in 1 Corinthians 6:13, but would like more detail specifically about the phrase “All things are lawful”. Is there any evidence outside the NT that it was a common saying?