How should this expression be used, and what is its origin?
Learn English – How to use the expression “lo and behold”
expressionsinterjections
Related Solutions
Citing Picturesque Expressions by Laurence Urdang, Facts on File Dictionary of Clichés (p.317), and the OED, Ken Greenwald had this comprehensive explanation of the phrase at Wordwizard:
PART AND PARCEL means essential portion or element, integral part, a vital part of a larger entity. <“Traveling was part and parcel of his sales position.”>. In this reduplicative phrase (repetition of an element), which has been common since the 14th century, the nouns ‘part’ and ‘parcel’ are synonyms and have been since the 14th century, ‘part’ being the older word (11th century) and ‘parcel’ (14th century) the newer. The alliteration and tautology/redundancy in the expression serve to emphasize the importance of a constituent to the whole. The expression has been used as a legal term from the mid-16th century on, principally for clauses of a law and for parts of a landholding. It didn’t start to be used in its present figurative sense until about 1800. ‘Part or parcel’ and ‘part nor parcel’ have also been used since the 16th century.
Earliest reference from OED:
1535-6 ‘Act 27 Henry VIII,’ c. 11 “This present Act, and euery PART AND PARCEL therof, shall extend [etc.]. Ibid. c. 26 The. . . . Lordships . . . to be PART AND PARCELL of the same hundred [of Wesebery].”
Earliest I can find via Google Books (from A Christian Directorie Guiding Men to Their Salvation, 1585):
I think the phrase you're looking for is actually pinch a loaf. This forum discussed its origins, with one person writing:
Amazingly enough, none of my references give the history of "pinch a loaf." But I'm guessing that the process of kneading and shaping dough gave rise to the expression.
This slang dictionary supports your intuition about what it means:
verb
to defecate.
He's in the bathroom pinching a loaf.
Another slang dictionary writes that the phrase is from 1994.
I have never, however, heard this phrase used. I'm an American English speaker, and at least in my experience this euphemism is not popular.
Best Answer
It is an interjection with literal meaning "look and see!" It is used to demonstrate surprise.
According to the Merriam-Webster dictionary, the first known use was in 1808.
As for the etymology, according to the Wiktionary, "lo originated from the shortening of the word look, commonly seen in Middle English texts".
Some interesting examples:
This Bob Dylan's song (1967).
We kept falling back, kept falling back, and lo and behold, after the '88 election, we found ourselves in the worst recession since the Great Depression. Bill Clinton, William J. Clinton (1998)
When the woman went to pick it up - lo and behold! - the cat was sitting quite comfy inside the cave. Rudyard Kipling, Just so stories for little children (1989)
But when she opened the door, lo, and behold! Jack wasn't there! Arthur Rackham, English fairy tales (1994)