Where does “大事に” come from?

大事に (Japanese) comes from Japanese に, from Old Japanese に.

大事に (Japanese): care deeply about, treat well

Definitions

  1. care deeply about, treat well

Ancestry of “大事に”, step by step

大事に traces back through two separate lines of ancestry.

via Japanese に

StepLanguageWordMeaning
1Japaneseにparticle for indirect objects; to; particle for...
2Old Japaneseに—

via Japanese 大事

StepLanguageWordMeaning
1Japanese大事An important thing; a serious matter; a valuable...
Every word from Old Japanese に →Every word from Japanese に →