You are strong, and the word of God lives in you
because you are strong,
and the word of God lives in you,
and you have overcome the evil one”
1 John 2:14
Doubtless to me the word “strong” (ἰσχυροὶ) here does not refer to physical strength. Instead it is an analogy comparing the ability of the physical body to do something — something probably difficult, that requires a lot of effort — to the young man’s struggles concerning the New Life.
Similarly the word “word” almost certainly does not mean a single unit of vocal expression which, if combine with others, form the basis of language and transmission of ideas. No. This is John writing, and he has already written a biography of Jesus that opens up by using the word “word” (λόγος, ου, ὁ) to mean Jesus.
Also the word “lives” (ESV “abides”) (μένει) does not mean “lives,” and though “abides” gets closer, it too retains the level of metaphor and does not state straightforwardly what is happening. Jesus, in the strictest sense possible, does not “live in you” because he is somewhere else: he is at the right hand of the Father, and not in you. Of course, when we say “Jesus lives in my heart” what we really mean is “the Holy Spirit lives in my heart,” which generally is close enough to the same thing.
But even this does not overcome the semantic ambiguity of “abides.” Jesus, the Holy Spirit, “God” in general — when one of these is said to “abide in you” it does not mean that they attain biological life and could be found if inter-intestinal microscopy was performed. Rather, this is a qualified life, a life that does not consist in biology but rather in the potential for interaction with other things that, by whatever means, also have the same potential. This comes in spiritual, not biological, life.
John is using metaphorical language, like we all do all the time. His point cannot be taken by skimming the metaphor by the surface; you have to dig at least one layer down to see what two things he is comparing using the metaphorical language.
This is all quite granular. But put it back together. John is saying that the young men who are part of his audience are able to do great things with respect to their New Life in Christ, because Christ had enabled them to do these things. God (in particular the Holy Spirit) has given this enabling.
Also, fun fact, these young men have overcome the evil one.
Just some thoughts from a bit of prep I am doing for a sermon next week, not even on this verse, but on 4:1-21.