for the love of

1. For the sake of, in consideration of. For example, She signed up for all these volunteer jobs for the love of praise . [c. 1200]

2. for the love of Pete or Mike or God . An exclamation of surprise, exasperation, or some similar feeling, as in For the love of Pete, give me the money! James Joyce used this idiom in Ulysses (1922): “For the love of Mike listen to him.” Pete and Mike are euphemisms for God. [Early 1900s] Also see for the sake of , def. 3.