True or truest?

But here’s the truth: what we do is not the truest thing about us. Building our identity on the foundation of what we do creates an identity that can crack or break or tumble down at any moment.— The Truest Thing about You, chapter 2

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But that's exactly what we do all the time. We take transient things about us and make them the absolute definition of who we are. The problem is that life is full of changes—and not all of them are better! If you have a minor (or major) setback/disappointment, you have to redefine yourself. Stress, anyone? But in Christ, we don't need to accept the merely true things as ultimate—that's what this book is all about—who you already are in Christ. And it's good news!

I read this in the electronic version, so I don't have page numbers, instead I will be citing the excerpts by chapter number.
</idle musing>