What does this quote mean?

“Holiness alone is undying peace.”

Allen contrasts lasting peace with temporary comfort or outward victory, then immediately connects the durable state he describes with self-control and an increasing orientation toward wisdom.

Source note: The Way of Peace, “The Realization of Perfect Peace,” Project Gutenberg #10740. The sentence follows Allen’s contrast between temporary peace from comfort or worldly victory and what he calls the enduring “Peace of Heaven”; the theological framework is retained rather than recast as clinical advice.

“The greatest remedy for anger is delay.”

Delay interrupts the first impulse of anger and gives judgment time to test whether the perceived offence deserves the reaction it initially provoked.

Source note: On Anger, Book II, section 29.

“Wisely and slow; they stumble that run fast.”

Speed without judgment can undermine the very goal a person is pursuing, so patience becomes part of effective action.

Source note: Act 2, Scene 3; Friar Laurence urges Romeo to move with greater care.

“For the wrath of man worketh not the righteousness of God.”

Anger is not automatically justified by intensity; the verse separates human wrath from the moral outcome a person may claim to be pursuing.

Source note: James 1:20 in the King James Version, immediately following the instruction to be slow to wrath.

“He will win who knows when to fight and when not to fight.”

Judgment includes restraint: choosing the wrong contest can be as damaging as fighting badly once the contest begins.

Source note: The Art of War, Chapter III, among Sun Tzu’s listed essentials for victory.

“Calmness of mind is one of the beautiful jewels of wisdom.”

Calmness is treated as a cultivated capacity arising from self-control and understanding rather than as a temperament a person either possesses or lacks.

Source note: As a Man Thinketh, chapter “Serenity”; Allen presents calmness as the result of long and patient effort in self-control.