In the well-known passage from Acts 17 where Paul speaks on the Areopagus about the unknown God, according to most Bible translations, Paul calls on the Greeks with whom he is talking to, to repent. Repentance is a well-known word in religious circles, but it is not the word Paul uses here. I do not deny that the word repent or turn back occurs in Scripture. That is indeed the case, see for example 2 Cor.3:16 and 1 Thess.1:9. But that is not what Paul says on the Areopagus.
Acts 17
30 God therefore, considering the times of ignorance, now commands all men everywhere to take heed.
The words that Paul speaks here are a conclusion to his argument that he makes for these philosophers. He appeals to their common sense and points to the One God, the Creator of everything and all. They knew many gods and therefore no God. After all, any god who has to share his power is not God in the absolute sense. That is to say: the Disposer of everything.
metanoia
The word that is rendered as to reptent in most Bible translations, such as the Statenvertaling and the NKJV translation, is the Greek word metanoia. This word is made up of two words: meta = after, with and the second part noia = thinking.
change
Meta points to a change and we still know it from our language in words such as metamorphosis. That is a change of form. So literally: a transformation.
We also find the word noia in our language, such as paranoia, which literally means thinking next to. A person who is paranoid has delusions. Thinking is derailed and therefore paranoia.
change of thinking
If we look at the word meta-noia with this information, it indicates a change of thinking: rethinking. That is why a translation with reflection fits perfectly, because that means: thinking, changing your mind.
one God
Acts 17 talks about the Greeks who worshipped many gods. Paul brings them the message that there is one God, who created everything, is Lord of all, gives everything to all and to whom all humanity belongs.
This was a radically different message for these Greeks: from many gods to one God. That overturned everything they had previously thought and hence Paul’s call for a change of mind. These Greeks would reflect on this.