for petes sake

[monster]

where does for petes sake come from

[Quizmonster]

St Peter supposedly stands guard at the gates of heaven, as God's sort of right-hand-man. So, saying something for his sake is much the same as saying it 'for God's sake', though without the element of possible blasphemy. It is a form of euphemism, in other words.

It might also just be a corruption of the other such phrase: 'for pity's sake'.