“For the sake of” vs “for sake of”

Question

Are for the sake of and for sake of both equally correct and idiomatic?

The dictionaries I know list only the former, while the latter also seems to be commonplace.

Answer 1

I don't recognise "for sake of" as an English phrase.

Looking at the iWeb corpus, I see that it does occur: 1990 instances, against 120670 of "for the sake of".

It is a much less common variant, and if I it occurred in something I was editing, I would regard it as a mistake, and add the "the".