"Sit" is from Middle English sitten, from Old English sittan, from Proto-West Germanic sittjan, from Proto-Germanic sitjaną, from Proto-Indo-European *sed- (“sit”).

"Lay" is from Middle English lay, from Old French lai, from Latin laicus, from Ancient Greek λαϊκός (laïkós).

In English, "sit" feels immediate and active where "lay" is passive and indirect. The distinction is both important and rooted in history.

It is incredibly stupid that we still have editors trying to force English poetry into Latinate forms almost a millenium after the battle of Hastings and all the consequent Anglo/Norman jockeying for position.