Where does “gambaru” come from?

gambaru (English) comes from Japanese 頑張る, from Japanese 眼張る, from Japanese 我に張る, from Japanese 我, from Old Japanese 我, from Old Japanese れ — nominalizing suffix used to form pronouns, often from demonstratives: one, thing.

gambaru (English): even with the hardest of tasks, in the context of Japanese culture

Definitions

even with the hardest of tasks, in the context of Japanese culture

Ancestry of “gambaru”, step by step

Step	Language	Word	Meaning
1	Japanese	頑張る	to work hard and do one's best to achieve a goal;...
2	Japanese	眼張る	to keep watch on something, to stare at something
3	Japanese	我に張る	to stick to one's beliefs
4	Japanese	我	first person singular pronoun: I, me, oneself;...
5	Old Japanese	我	first-person personal pronoun: I, me;...
6	Old Japanese	れ	nominalizing suffix used to form pronouns, often from demonstratives: one, thing

Every word from Old Japanese れ →Every word from Old Japanese 我 →Every word from Japanese 我 →