In the exposition of the book, the dominant theme of the overwhelming power of Big Brother is evident. Winston is the lens through which we can better understand the power and totalizing control of Big Brother in Oceania. The opening description of the inner stairwell inside Victory Mansions conveys this power:
The flat was seven flights up, and Winston, who was thirty-nine and had a varicose ulcer above his right ankle, went slowly, resting several times on the way. On each landing, opposite the lift-shaft, the poster with the enormous face gazed from the wall. It was one of those pictures which are so contrived that the eyes follow you about when you move. BIG BROTHER IS WATCHING YOU, the caption beneath it ran. (Ch. 1)
Even in something as small as a building stairwell, the power of Big Brother is inescapable. The poster, its eyes, and the caption are able to cast a literal and figurative shadow on the life Winston leads and the lives of all the people of Oceania.
In Chapter 2, Orwell describes the Parsons' home as "dingy in a different way." Its difference from Winston's own home is cosmetic because the unifying force of Big Brother's power is present in this setting, as Winston surveys its interior. The posters of Big Brother are one element in which Big Brother is present in the home. Yet, the more sinister power of Big Brother in the Parsons' home is their children. Complete devotees of Big Brother, their presence represents the power of the government in the lives of its citizens:
With those children, he thought, that wretched woman must lead a life of terror. Another year, two years, and they would be watching her night and day for symptoms of unorthodoxy.... On the contrary, they adored the Party and everything connected with it. The songs, the processions, the banners, the hiking, the drilling with dummy rifles, the yelling of slogans, the worship of Big Brother -- it was all a sort of glorious game to them. All their ferocity was turned outwards, against the enemies of the State, against foreigners, traitors, saboteurs, thought-criminals. It was almost normal for people over thirty to be frightened of their own children.
Here again, the power of Big Brother can be seen in how "it was almost normal for people over thirty to be frightened of their own children." The fact that children of Oceania all participate in a "willing worship of Big Brother" represents the government's ultimate power.
Finally, I would suggest that Big Brother's power can be seen in the national presence of Newspeak. Winston's job in the Ministry of Truth exposes him to how Big Brother's power even exists in the domain of language:
Winston examined the four slips of paper which he had unrolled. Each contained a message of only one or two lines, in the abbreviated jargon -- not actually Newspeak, but consisting largely of Newspeak words -- which was used in the Ministry for internal purposes:
times 17.3.84 bb speech malreported africa rectify
times 19.12.83 forecasts 3 yp 4th quarter 83 misprints verify current issue
times 14.2.84 miniplenty malquoted chocolate rectify
times 3.12.83 reporting bb dayorder doubleplusungood refs unpersons rewrite fullwise upsub antefiling (Ch. 4)
This passage reflects Big Brother's power extends into the realm of language and communication. Newspeak is the official language that Big Brother controls and embodies the government's total power.