It is Christmas Eve, and Scrooge is about to shut up his counting house for the night. Bob Cratchit is about to leave and Scrooge sourly enquires:

You’ll want all day to-morrow, I suppose?

Bob confirms that he would like to take Christmas Day as a holiday, if it is convenient, but Scrooge seizes on this form of words, which is really just a matter of courtesy, and replies that is not convenient at all, neither is it fair. He points out that Bob would presumably be aggrieved if Scrooge were to withhold his pay of half a crown for that day, yet Bob does not think it unfair for Scrooge to pay him for a full day on which he does no work. Bob points out that it is only once a year, to which Scrooge replies:

A poor excuse for picking a man’s pocket every twenty-fifth of December!...But I suppose you must have the whole day. Be here all the earlier next morning.

Scrooge's argument is that he must pay for a full day's work without receiving any benefit in return, and that this is essentially the same as having the money stolen from him. This sounds fairly reasonable, if rather joyless, but in the Victorian era, as today, holidays were factored in to the total salary paid. Both Scrooge and Bob presumably know this, so it seems that Scrooge is merely being curmudgeonly rather than attempting to make a serious economic point.