What does this quote mean?

“It was the best of times, it was the worst of times.”

Opposing conditions can exist at the same time, making an era or a life impossible to reduce to a single description.

Source note: A Tale of Two Cities, opening sentence.

“To every thing there is a season, and a time to every purpose under the heaven.”

The verse places change inside a larger rhythm of seasons and purposes, making it useful for thinking about acceptance when one phase of life gives way to another.

Source note: Ecclesiastes 3:1 in the King James Version, opening the sequence of contrasting times and seasons.

“The mass of men lead lives of quiet desperation.”

Thoreau challenges ordinary routines by suggesting that outward normality can hide inward dissatisfaction.

Source note: Walden, “Economy”; Thoreau contrasts outwardly conventional lives with concealed dissatisfaction in his opening critique of ordinary economic arrangements.

“In a world where all is fleeting, change alone endures.”

Stability is temporary, so practical judgment requires expecting change rather than treating present arrangements as permanent.

Source note: Counsels and Maxims, T. Bailey Saunders translation, in a discussion of fortune and apparent stability.

“Circumstance does not make the man; it reveals him to himself.”

Circumstances can expose habits of thought and character that were already present, turning difficulty into information about what needs attention or change.

Source note: As a Man Thinketh; Allen uses circumstance as a mirror for character and habitual thought.

“Life is a succession of lessons which must be lived to be understood.”

Some understanding arrives only through experience: ideas about character, consequence, relationship, and judgment become clearer when they have been lived rather than merely described.

Source note: The Conduct of Life; the line connects knowledge of life with accumulated experience and the lessons that experience makes intelligible.