Quote 1
"I ventured to think," stammered Bernard, "that your fordship might find the matter of sufficient scientific interest…"
"Yes, I do find it of sufficient scientific interest," said the deep voice. "Bring these two individuals back to London with you." (9.9-10)
Bernard uses "science" to cloak his selfish motivations (i.e., preventing his own deportation to an island).
Quote 2
"Adults intellectually and during working hours," he went on. "Infants where feeling and desire are concerned."
[…]
[…] "It suddenly struck me the other day," continued Bernard, "that it might be possible to be an adult all the time."
"I don't understand." Lenina's tone was firm.
"I know you don't. And that's why we went to bed together yesterday—like infants—instead of being adults and waiting." (6.1.65-9)
Or, don't go to "Symbols, Imagery, Allegory" and instead just let Bernard sum it up for you here.
Quote 3
To have dealings with members of the lower castes was always, for Bernard, a most distressing experience. For whatever the cause (and the current gossip about the alcohol in his blood-surrogate may very likely—for accidents will happen—have been true) Bernard's physique was hardly better than that of the average Gamma. He stood eight centimetres short of the standard Alpha height and was slender in proportion. Contact with members of the lower castes always reminded him painfully of this physical inadequacy.
[…]
"Hurry up!" said Bernard irritably. One of them glanced at him. Was that a kind of bestial derision that he detected in those blank grey eyes? "Hurry up!" he shouted more loudly, and there was an ugly rasp in his voice. (4.2.3-5)
Bernard isn't satisfied with his intellectual superiority. For him, power is threatened by physical inadequacy. Of course, the only threat to his authority is his own doubt. Confidence—it's a tricky business.