People often use the expression “kindred spirit” to describe that one person in their life who gets them. In Philippians 2:20 Paul writes of Timothy, “For I have no one else of kindred spirit who will genuinely be concerned for your welfare.” So of course, I was curious. The expression “kindred spirit” is one word in Greek (isopsuchos – ἰσόψυχος) and it is used only here in the New Testament. This creates a bit of a problem lexically because we have no other uses of the term in the New Testament to observe in various contexts. A synchronic approach, observing how words are used in the same time frame is preferable to a diachronic approach, observing how words have been used through time because words shift emphasis and meaning over time. In addition, attempting to determine a word’s lexical force diachronically is always suspect when breaking down words by root and compounds. For instance, the term “bookcase” is relatively transparent etymologically speaking: it is a case for books. However, there are major limitations with such an approach (e.g. “butterfly”). The term isopsuchos (ἰσόψυχος) is such a compound term, built from the adjective isos (ἴσος) meaning “equal” and the noun psuchē (ψυχή) meaning “soul.” As a result, major lexicons give it the gloss of “like soul/mind” (BDAG).
As a result of limited synchronic uses, we must look to the Septuagint for lexical examples, though such uses would of course be earlier. Ironically, there is only one use here as well! But the usage in Psalm 54:14 (55:13 in English versions) gives us some contextual help with meaning as does Philippians 2:20. In the Psalm, David declares, “But it you, a man my equal, my companion and my familiar friend.” A kindred spirit is a friend, an equal. There is a familiarity with them. The rest of the context denotes the fellowship he once enjoyed (but subsequently lost). Paul writes of Timothy that he was one “who will genuinely be concerned for your welfare.” In other words, Timothy would be as concerned for them as Paul would. They were “kindred spirits” in terms of ministry. They had the same pastoral philosophy for shepherding sheep.
There are a host of realms in life where we might have kindred spirits, people we share similar interests and passions: sports, literature, pets, cooking, vocation, etc. But the deepest of these relationships will always be in the realm of faith. Such kindred spirits are those with whom we will spend eternity.