In the passage below, the word “as” can mean ‘as though’ or ‘while.’ This is so in the Hebrew and Greek Old Testament:
“You shall not hate your brother in your heart, but you shall reason frankly with your neighbor, lest you incur sin because of him. You shall not take vengeance or bear a grudge against the sons of your own people, but you shall love your neighbor as yourself: I am the LORD. (Leviticus 19:17-18)
Most interpreters take the word ‘as’ to mean ‘as though.’ So ‘love your neighbor as though he were yourself.’ But it might be a useful thought experiment to think of it this way, ‘love [seek the well-being of] your neighbor as you love [seek the well-being] of yourself.’ I’m not saying that’s what the passage means. I’m just saying that it’s suggestive. Below is a paragraph from Marcus Aurelius about doing good by others in such a way that it benefits more than just them:
This will be clearer to you if you remind yourself: I am a single limb (melos) of a larger body— a rational one. Or you could say “a part” (meros)— only a letter’s difference. But then you’re not really embracing other people. Helping them isn’t yet its own reward. You’re still seeing it only as The Right Thing To Do. You don’t yet realize who you’re really helping.
Aurelius, Marcus. Meditations: A New Translation (Modern Library) (Kindle Locations 1657-1661). Random House Publishing Group. Kindle Edition.
And so such a thought experiment might go: as I do what is best for myself, how might I do it in such a fashion that it is a blessing to others? Or, to put it the other way, how might I do what it best for others in a way that is good for myself and my family as well?