go so far as to say

go so far as to say something

to put something into words; to risk saying something. I think that Bob is dishonest, but I wouldn't go so far as to say he's a thief. Red meat may be harmful, but I can't go so far as to say it causes cancer.
See also: far, say
References in classic literature ?
I won't go so far as to say everything,' returned Mr Boffin, on whom his manner seemed to grate, 'because there's some things that I never found among the dust.
I would not go so far as to say she believed it altogether.