The verb to sack (someone) means to dismiss (someone) from employment. This verb seems to have appeared in the first half of the 19th century. For example, the Perthshire Courier (Scotland) of Thursday 29th April 1841 reported that at the Glasgow assizes, during the trial for the murder of a superintendent of Railway labourers, one of the accused, Denis Doolan, allegedly said to a witness that

he had been sacked by the ganger; Doolan said he had beat the ganger for it.

The verb to sack is from to give the sack, to dismiss from employment, and to get the sack, to receive one’s dismissal.

Earlier versions used the nouns bag and canvas. To give the bag means to dismiss, but originally had the opposite signification: to leave without warning. For example, in A quip for an vpstart courtier: or, A quaint dispute between veluet breeches and cloth-breeches Wherein is plainely set downe the disorders in all estates and trades (1592), the English writer and playwright Robert Greene (1558?-1592) thus addressed the shoemakers:

Well for your knauery, you shall haue those cursses which belongs vnto your craft: you shall bee light footed to trauell far, light witted vpon euery small occation to giue your maister the bag.

In A Glossary of the dialect of Almondbury and Huddersfield (West Yorkshire), published in 1883, Alfred Easther wrote:

Bag, notable for the expression, ‘to give the bag,’ which is to dismiss; or ‘to get the bag,’ i.e. to be dismissed. In some parts to give and get ‘the sack.’ The word has long been known in this sense [the author quotes the above-mentioned passage from A quip for an vpstart courtier].

The English playwright James Shirley (1596-1666) used to receive the canvas, meaning to receive one’s dismissal, in The Brothers (1626):

                                                        I lose
My honor, if my Don receive the canvas.
He ha’s a good estate, and I have borrow’d
Considerable monies of him Sister,
Peeces of eight, and transitory Ducats.

The versions with sack seem to date from the early 19th century. The Dublin Evening Mail of Friday 6th October 1826 published an Ode to the Opposition which contains the following:

Ye factious, place-hunting and waspish crew,
Who love to rail at Ministers and taxes,
[…]
The Ministry, you hope, may get the sack.

And The Liverpool Mail of Thursday 22nd September 1836 wrote in London Police Report that a certain John Norrey was brought before the Lord Mayor for having tried to sell a piece of cloth in the street; he had said:

“I’m blowed if I didn’t cabbage [= steal] it from my master, and if he knowed it he’d give me the sack.”

It is generally said that the expressions to give/get the sack (or the bag, or the canvas) were taken from the practice of journeymen mechanics who travelled in quest of work carrying their own tools in a bag. When they were discharged, their employers handed them back the bag, where their tools had been packed up preparatory to their removal.

However, nothing seems to corroborate this theory, which anyway does not account for the original meaning of to give the bag, to leave without warning.

 

IN FRENCH

 

The verb saquer, or sacquer, attested in 1866, also means to dismiss from employment.

It is apparently from the obsolete phrase donner (à quelqu’un) son sac et ses quilles, literally to give (someone) their bag and their skittles, recorded by Randle Cotgrave in A Dictionarie of the French and English Tongues (1611):

Donner son sac, & ses quilles à. On luy a donné son sac, &c. [= He has been given his bag, etc.] He hath his pasport giuen him, he is turned out to grazing; (said of a seruant whom his maister hath put away.)

In Dictionnaire de la langue française (1869), the French lexicographer Émile Littré (1801-81) explained the following phrases under the headword sac [= bag]:

Le sac et les quilles, les quilles avec le sac pour les enfermer quand on ne joue plus.
Figuré. Trousser son sac et ses quilles, prendre son sac et ses quilles, prendre ses hardes et s’en aller.
Donner à quelqu’un son sac et ses quilles, mettre quelqu’un dehors, s’en défaire.
Figuré. Avoir son sac et ses quilles, être chassé. […]
Figuré. Ne laisser aux autres que le sac et les quilles, prendre le meilleur et laisser aux autres ce qui ne vaut rien, proprement prendre l’argent du jeu et ne laisser aux autres que les quilles et leur sac.
translation:
The bag and the skittles, the skittles with the bag to put them in when one no longer plays.
Figurative. To take one’s bag and skittles, to take one’s belongings and leave.
To give someone their bag and skittles, to throw someone out, to get rid of them.
Figurative. To have one’s bag and skittles, to be turned out. […]
Figurative. To let the others have only the bag and the skittles, to take the best and let the others have what is worthless, properly to take the winnings and let the others have only the skittles and their bag.