All one needs to do is read the parable in context.
45 "Who then is the faithful and wise servant, whom the master has put in charge of the servants in his household to give them their food at the proper time? 46 It will be good for that servant whose master finds him doing so when he returns. 47 I tell you the truth, he will put him in charge of all his possessions. 48 But suppose that servant is wicked and says to himself, 'My master is staying away a long time,' 49 and he then begins to beat his fellow servants and to eat and drink with drunkards. 50 The master of that servant will come on a day when he does not expect him and at an hour he is not aware of. 51 He will cut him to pieces and assign him a place with the hypocrites, where there will be weeping and gnashing of teeth.
The Society claims that the "coming" in this parable refers to a past event, Jesus "coming" into his "temple" in 1919. Notice v. 50, the refrain that the master of the servant within the parable "will come on a day when he does not expect him and at an hour he is not aware of." Now go back a few verses to the preceding parable:
42 "Therefore keep watch, because you do not know on what day your Lord will come. 43 But understand this: If the owner of the house had known at what time of night the thief was coming, he would have kept watch and would not have let his house be broken into. 44 So you also must be ready, because the Son of Man will come at an hour when you do not expect him.
This is talking about the same thing, it makes the same point as the parable immediately following it, that the Son of Man will come at a day and hour when his servants do not expect him. Yet the Society misses this obvious parallel and regards this parable as referring to an altogether different "coming", one that still lies in the future. The passage of the discourse immediately preceding this again makes the same point:
36 "No one knows about that day or hour, not even the angels in heaven, nor the Son, [ f ] but only the Father. 37 As it was in the days of Noah, so it will be at the coming of the Son of Man. 38 For in the days before the flood, people were eating and drinking, marrying and giving in marriage, up to the day Noah entered the ark; 39 and they knew nothing about what would happen until the flood came and took them all away. That is how it will be at the coming of the Son of Man. 40 Two men will be in the field; one will be taken and the other left. 41 Two women will be grinding with a hand mill; one will be taken and the other left.
Again, the same thing. The coming of the Son of Man is a sudden event like the Flood that will come without warning; we encounter the same theme here, that no one would know the day or hour when the coming occurs. The Society regards this as a future coming, not one that supposedly already occurred back in 1919. And what is the "coming of the Son of Man"? This event was already described earlier in the discourse:
27 For as lightning that comes from the east is visible even in the west, so will be the coming of the Son of Man. 28 Wherever there is a carcass, there the vultures will gather. 29 Immediately after the distress of those days, 'the sun will be darkened, and the moon will not give its light; the stars will fall from the sky, and the heavenly bodies will be shaken.' [ c ] 30 "At that time the sign of the Son of Man will appear in the sky, and all the nations of the earth will mourn. They will see the Son of Man coming on the clouds of the sky, with power and great glory. 31 And he will send his angels with a loud trumpet call, and they will gather his elect from the four winds, from one end of the heavens to the other.
The coming is again sudden and visible to all, like lightning that lights up the sky. The Society presently regards the coming of the Son of Man as future, not a past "coming" back in 1914 or 1919 (this was the belief prior to 1995). So only with special pleading is the Society able to disassociate the parable of the faithful and wise servant (v. 45-51) from the whole preceding context and regard it as referring to a different coming altogether.
BTW, the text uses the terms erkhomai "come" and parousia "coming, arriving" interchangeably, which used to be basis for the Society to claim that two different comings are meant in the discourse, with the parousia occurring back in 1914. It is worth pointing out however that parousia is not used in the parable of the faithful and wise servant; the word used in v. 46, 50 is the usual word for "come", the same word that occurs in v. 30, 38-44 (passages that the Society considers as referring to the future).
