Quote 4
The most racking pangs succeeded: a grinding in the bones, deadly nausea, and a horror of the spirit that cannot be exceeded at the hour of birth or death. Then these agonies began swiftly to subside, and I came to myself as if out of a great sickness. There was something strange in my sensations, something indescribably new and, from its very novelty, incredibly sweet. I felt younger, lighter, happier in body; within I was conscious of a heady recklessness, a current of disordered sensual images running like a millrace in my fancy, a solution of the bonds of obligation, an unknown but not an innocent freedom of the soul. I knew myself, at the first breath of this new life, to be more wicked, tenfold more wicked, sold a slave to my original evil; and the thought, in that moment, braced and delighted me like wine. I stretched out my hands, exulting in the freshness of these sensations; and in the act, I was suddenly aware that I had lost in stature. (10.4)
Dr. Jekyll describes in very positive terms how it feels to be free "of the bonds of obligation." This is why Mr. Hyde is able to take over his body and mind.
Quote 5
That night I had come to the fatal cross-roads. Had I approached my discovery in a more noble spirit, had I risked the experiment while under the empire of generous or pious aspirations, all must have been otherwise, and from these agonies of death and birth, I had come forth an angel instead of a fiend. The drug had no discriminating action; it was neither diabolical nor divine; it but shook the doors of the prison-house of my disposition; and like the captives of Philippi, that which stood within ran forth. At that time my virtue slumbered; my evil, kept awake by ambition, was alert and swift to seize the occasion; and the thing that was projected was Edward Hyde. Hence, although I had now two characters as well as two appearances, one was wholly evil, and the other was still the old Henry Jekyll, that incongruous compound of whose reformation and improvement I had already learned to despair. The movement was thus wholly toward the worse. (10.8)
Dr. Jekyll produces an evil version of himself—is this success or failure at separating good from evil?
Quote 6
Between these two, I now felt I had to choose. My two natures had memory in common, but all other faculties were most unequally shared between them. Jekyll (who was composite) now with the most sensitive apprehensions, now with a greedy gusto, projected and shared in the pleasures and adventures of Hyde; but Hyde was indifferent to Jekyll, or but remembered him as the mountain bandit remembers the cavern in which he conceals himself from pursuit. Jekyll had more than a father's interest; Hyde had more than a son's indifference. To cast in my lot with Jekyll, was to die to those appetites which I had long secretly indulged and had of late begun to pamper. To cast it in with Hyde, was to die to a thousand interests and aspirations, and to become, at a blow and forever, despised and friendless. The bargain might appear unequal; but there was still another consideration in the scales; for while Jekyll would suffer smartingly in the fires of abstinence, Hyde would be not even conscious of all that he had lost. Strange as my circumstances were, the terms of this debate are as old and commonplace as man; much the same inducements and alarms cast the die for any tempted and trembling sinner; and it fell out with me, as it falls with so vast a majority of my fellows, that I chose the better part and was found wanting in the strength to keep to it. (10.16)
Choosing between good and evil is not an easy choice, and comes with many consequences.