THIS MIGHT SURPRISE YOU
The answer
Nowhere. Lahmi appears once in the Bible, in 1 Chronicles 20:5. The same fight in 2 Samuel 21:19 has Elhanan kill "Goliath the Gittite" himself, with the same spear "like a weaver's beam." Chronicles gives the dead man a name of his own and makes him Goliath's brother.
Why it’s interesting
The New Oxford Annotated Bible reads 1 Chronicles 20:5 as a way to keep two stories from Samuel true at once. If Elhanan's man is Goliath's brother, then David's kill and Elhanan's kill can both stand. Elhanan's father changes between the books too, Jaare-oregim in Samuel and Jair in Chronicles.
Scholarly consensus
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