Adversity tests self on the strength of self-confidence, self-preservation and self-discipline while power tests the instinctive promotion of self against the altruistic servitude to selfless. The worth of a man who could stand adversity and preserve self is diametrically different from the worth of man who could place selflessness above self-interest.
In my career, I seen at first hand the different behaviours of many leaders at various levels within many different companies. These leaders control resources, assignments, staff welfare, staff job distributions and thus indirectly control financial remuneration and wellbeing of their co-workers. They are expected to allocate resources fairly, treat staff fairly and equitably to advance the missions of the company as a whole. Through observations of them over the years, I have come to appreciate the gist of Lincoln's well articulated statement.
Most of these leaders were selected essentially on their ability to stand adversity and preserve self e.g. ability to handle undue stress, successfully handling tremendously heavy workload and complicated deals on impossible timelines. Sometimes they even resort to under-hand or under-table shady tactics to succeed in the tedious assignments or difficult deals and to manipulate situations and people to their advantage.
Unfortunately, when they get promoted to a higher level, they are now vested with power to work against the very grain of the quality that selected them for the job. Overnight they are expected to transition from self-centric to selfless missions and to use power responsibly for the good of their unit or company. Not unexpectedly, this does not always...