needless to say; it goes without saying
Used to introduce something obvious or universally accepted, often at the beginning of a statement.
断るまでもなく、健康は何よりも大切だ。
Needless to say, health is more important than anything.
断るまでもなく、彼はその仕事を引き受けた。
It goes without saying that he accepted the job.
Variant with 無く instead of なく; slightly more formal or literary feel.
From 断る (to refuse, to decline) + までもなく (even without doing). Literally 'even without refusing', it evolved to mean something so obvious that there is no need to refuse or object.