This objection aims to dismiss your truth-claims as overrated. It’s a strategy for leveling out all assertions as no more than mere personal opinions: “You say to-may-to, I say to-mah-to.”
Here are some things to keep in mind.
One, stay focused on what C. S. Lewis called “mere Christianity” — the core truths of the gospel that are super-clear in the Bible. Avoid pet doctrines and denominational nuances. Your unbelieving friend might be throwing this objection out there because you really are advocating just a personal hunch.
Two, validate the objection, then neutralize it. “Sure, there’s interpretation in what I’m saying. But no one can know anything without interpreting it, without running it through the sieve of personal understanding. It’s like the sunlight shining through a stained-glass window. The colors show up, but the light is still real and the sun is really out there. So okay, you’re getting the gospel through me, and I’m not very good at this. Big deal. The point is, it isn’t JUST my interpretation. There is truth in what I’m saying.”
Three, make the truth personal, and offer it personally to your friend. “I always have to watch myself, to minimize the distortion-factor in my thinking about Christ. So, thank you for reminding me of that. But here’s what I can’t get away from. As I read the Bible, the reality of Christ comes storming through to me so clearly I just can’t dismiss that power as an ‘interpretation.’ I have to deal with him, because he’s dealing with me. If you’d rather keep it safe, at the level of ‘interpretation,’ I don’t blame you. He is totally rocking my world. But here’s where I come down. I’d rather have him messing with me than lose him by treating him as an abstraction. His love is the only good thing in my life more then my wife that I’ll keep forever!