pray tell

Etymology
From +.

Interjection

 * 1)  Please explain (something the requester does not yet understand).
 * 2)  Expressing incredulity, please explain (some claim or position the speaker doubts).
 * 1)  Expressing incredulity, please explain (some claim or position the speaker doubts).

Usage notes
When "pray" was used to emphasize requests, this standard construction (as, "pray come here", "pray help us", "pray leave me") was an earnest request for information. The phrase is now, however, usually used ironically to emphasize the unacceptability of something, especially when highlighting a logical fallacy.