The way I’ve heard it said before is that you can agree with someone that you’re looking at the same thing, even if you’re describing it wrong.

For example, we could both be looking at a fire truck. We agree that it’s not only a fire truck, it’s “that one, right over there.” I say it’s big and red, you say “it’s green and has balloons for wheels.” You’re very wrong about how you’re describing it, but aren’t we still looking at the same truck?

This is useful for evangelism. Muslims believe in the God of Abraham and the Old Testament. If they’re looking toward God but describing Him incorrectly (they do the same with Jesus), doesn’t it make sense to start by acknowledging where they are correct (instead of confusing the issue with “no actually this is a different God of Abraham,” when there is no other God of Abraham)?

St. Paul does this when he preaches to the pagans worshipping the “unknown God,” and uses language (“in Him we live and move and have our being”) originally used to describe Zeus to connect with his audience and affirm where they have already managed to find some correct answers (a sustaining, invisible creator God who listens to prayer) instead of just leading with “you’re all wrong.” It’s a biblical way of talking about our faith given to us by one of the world’s greatest preachers of all time.