In what play did Shakespeare use the phrase "bag and baggage?"
The quotation by William Shakespeare that you are referring to was found in the play As You like it. It is based on an old military saying. "Bag and baggage" meant both men and their personal and/or military materials. It was used in the context of armies being able to retreat with some semblance of order, without leaving their goodies behind for the enemy to use or loot.
Shakespeare uses it like this:
"Let us make an honorable retreat, though not with bag and baggage, yet with scrip and scrippage."
"Scrip" is another word for what we would call paper money, or maybe even checks. The idea here is that they would be retreating honorably, and though leaving their stuff behind, they would be bringing their cash.
Though Shakespeare has coined more of our words and phrases than most of us even realize, this one pre-dates him. The phrase "bag and baggage" is from Shakespeare's comedy As You Like It, written in 1600. The earliest written reference in English dates from the 1500s. As You Like It is one of Shakespeare's many "comedy of error" type plots, with mistaken identity and mistaken gender!
The line which contains the phrase in question is found in Act III, Scene ii of the play, lines 153-155: "Let us make an honorable retreit, though not with bagge and baggage, yet with scrip and scrippage."
This phrase was spoken by Touchstone in Act 3, Scene 2 of As You Like It. Celia, Rosalind's cousin, had just come to realize that it was Orlando, Rosalind's love interest, who had been hanging love poems to Rosalind on the branches of trees and shrubs. At this point, Rosalind and Celia are disguised as Ganymede and Aliena, but that's an other matter.
Touchstone, the court jester, who had accompanied (and helped protect) the two young women on their trip to the surreal Forest of Arden, alertly comes to recognize the power of the moment, Celia crying out (knowing it is Orlando showing interest in Rosalind) "O wonderful, wonderful, and most wonderful, and yet again wonderful, and after that out of all whooping."
It's at this point when Touchstone says to Corin the Shepherd (I think it was) that the two of them should leave this moment to the women and scat, though "not with bag and baggage, yet with scrip and scrippage" meaning with their wallets with such things as cash, cards and ID, but that they should leave all else behind.
This represents a great moment in As You Like It. Orlando soon enters saying "I am he that is so love-shaked." Rosalind (disguised still as Ganymede) tells him "Love is merely a madness. I profess curing it by counsel." As for the counsel, she tells him that he needs to "come every day to my cottage and woo me." Rosalind is good. She has to be one of Shakespeare's great female leads.
If you have an interest in following up with this nifty moment in Shakespeare, I suggest you visit www.abbreviatedshakespeare.com and then look at the attachment titled Enchantment found in Act 3, Scene 2.