I’ve mentioned before that sometimes questions will pop into my head for no reason at all and nag me to answer them; I was literally washing my dinner dishes when this question wandered into my brain unprovoked.
Western culture* has a tenet that one’s most loyal and trusted advisor/soldier/business partner is one’s “right-hand man.” But why? My immediate thought was that it’s born of religion because I’ve studied both the Tanakh and the Bible at some length, and I know the lyrics to ‘Once in Royal David’s City’ and ‘Heaven on Their Minds’.** It’s also the most obvious answer because that phrasing shows up nearly three dozen times over both scriptures.***
But it’s not the right answer. It seems those two documents absorbed some combat history.
In all likelihood the concept of the person to your right being the person you trust the most because he’s the person on whom you rely the most (and therefore being your “right-hand man” comes from the phalanx formation. In the phalanx, the person on your right was the one using his shield to protect your entire right side — including, since roughly 85% of the population are right-handed****, your sword hand. This actually raises a whole separate question about where they put lefties. Did they have entire phalanxes of lefties that were mirror images of the right-handed phalanxes? Did they simply train lefties to fight right-handed? If I can find that answer, you can be sure I’ll let you know.
Interestingly, though we generally associate the phalanx with the ancient Greeks — specifically the Spartans if you payed attention in grade 9 World History — the first known depiction of the formation is actually a fragment of the Sumerian Stele of the Vultures, which dates to the 25th century BCE.
You can read more here. Of course, I would be remiss if I failed to mention that there’s no definitive answer to this question and if you google the origins, many, many (most) people submit JESUS! as the answer. Which is fine, if not particularly logical. Just because it appears in scripture doesn’t make it the origin; I choose logic.
*I don’t know enough about Eastern culture to comment on the validity of the idiom there.
**I’d urge you to take those two pieces for what they’re worth.
***1 Kings 2:19, Ezekiel 16:46, Ezekiel 21:22, Zechariah 3:1, 1 Chronicles 6:39, 2 Chronicles 18:18, Psalms 16:8, Psalms 77:10, Psalms 80:17, Psalms 91:7, Psalms 109:6 and 109:31, Psalms 110:1 and 110:5 — the first of which is directly referenced in Matthew 22:44, Mark 12:36, Luke 20:42, and Acts 2:34, and Hebrews 1:13 — Matthew 26: 64, Mark 14:62, Mark 16:19, Luke 22:69, Acts 2:33, Acts 5:31, Acts 7:55 and 7:56, Romans 8:34, Ephesians 1:20, Colossians 3:1, Hebrews 1:3, Hebrews 12:2, and 1 Peter 3:22. Lest you think I just know those offhand, remember I’m really good at finding things and very patient in my research. Also, given that John is our non-synoptic friend, his absence from this list shouldn’t be particularly surprising.
****Though, as with the blue eyes, a disproportionate number of actors are lefties. Pay attention the next time you see an actor writing something onscreen. I promise you more of them will be left-handed than is representative of the actual population.