Sumner recovered his health, while his beloved sister Mary, at the age of twenty-two, faded from his sight by consumption. He wrote his brother George: "She herself wished to die; and I believe that we all became anxious at last that the angel should descend to bear her aloft. From the beautiful flower of her life the leaves had all gently fallen to the earth; and there remained but little for the hand of death to pluck. During the night preceding the morning on which she left us, she slept like a child; and within a short time of her death, when asked if she were in pain, she said, 'No; angels are taking care of me.'"

To Charles Sumner this death was an incomparable loss. She was especially beautiful and lovely, and the idol of his heart. Possibly it helped to make him ready for his great work.

Into most lives, especially those designed for great deeds, there seem to come decisive moments when events open the door from the darkness of obscurity into the noonday glare of fame. Such a time came to Sumner in 1845. He was asked to deliver the usual Fourth of July address at Tremont Temple, Boston, as Charles Francis Adams, Horace Mann, and others had done in previous years. He chose for his subject "The True Grandeur of Nations," showing that the "true grandeur" is peace and not war. He dealt vigorously with the Mexican War, then impending, as a result of the annexation of Texas, with consequent enlargement of slave territory.

Sumner was now thirty-four, well developed physically, his face handsome and radiant as ever, with the smile of his boyhood, his voice clear and resonant, his mind full to overflowing. He spoke for two hours, without notes. He said: "The true greatness of a nation cannot be in triumphs of the intellect alone. Literature and art may widen the sphere of its influence; they may adorn it; but they are in their nature but accessories. The true grandeur of humanity is in moral elevation, sustained, enlightened, and decorated by the intellect of man.... In our age there can be no peace that is not honorable; there can be no war that is not dishonorable. The true honor of a nation is to be found only in deeds of justice and beneficence, securing the happiness of its people,—all of which are inconsistent with war. In the clear eye of Christian judgment, vain are its victories, infamous are its spoils. He is the true benefactor, and alone worthy of honor, who brings comfort where before was wretchedness; who dries the tear of sorrow; who pours oil into the wounds of the unfortunate; who feeds the hungry, and clothes the naked; who unlooses the fetter of the slave; who does justice; who enlightens the ignorant; who, by his virtuous genius in art, in literature, in science, enlivens and exalts the hours of life; who, by words or actions, inspires a love for God and for man. This is the Christian hero; this is the man of honor in a Christian land."

The believers in war felt somewhat hurt by Sumner's plainness of speech, but the city of Boston and the State of Massachusetts awoke to the knowledge of an eloquent man in their midst, who had doubtless a work before him. Mrs. Lydia Maria Child wrote him: "How I did thank you for your noble and eloquent attack upon the absurd barbarism of war! It was worth living for to have done that, if you never do anything more. But the soul that could do that will do more."

Chancellor Kent wrote him, "I am very strongly in favor of the institution of a congress of nations or system of arbitration without going to war. Every effort ought to be made by treaty stipulation, remonstrance, and appeal to put a stop to the resort to brutal force to assert claims of right. The idea of war is horrible. I remember I was very much struck, even in my youth, by the observation (I think it was in Tom Paine's 'Crisis') that 'he who is the author of war lets loose the whole contagion of hell, and opens a vein that bleeds a nation to death.'"

Seven thousand copies of this oration were distributed by the Peace Societies of England, and it had a wide reading in our own country.

Sumner was now called upon to speak with Garrison, Phillips, and others, on the question of the annexation of Texas with her slave territory. He said, "God forbid that the votes and voices of the freemen of the North should help to bind anew the fetters of the slave! God forbid that the lash of the slave-dealer should be nerved by any sanction from New England! God forbid that the blood which spurts from the lacerated quivering flesh of the slave should soil the hem of the white garments of Massachusetts."

The educated Boston lawyer, the friend of hosts of authors and jurists on both sides of the ocean, the accomplished and aristocratic scholar, Sumner had placed himself among the despised Abolitionists! Many of his friends stood aghast, even refusing to recognize him on the street. This act required great moral heroism, but he was equal to the occasion. The door had opened to fame and immortality, even though they came to him through contumely and well-nigh martyrdom.

In 1846, Mr. Sumner spoke before the Phi Beta Kappa Society of Harvard University: "We stand on the threshold of a new age, which is preparing to recognize new influences. The ancient divinities of violence and wrong are retreating to their kindred darkness. The sun of our moral universe is entering a new ecliptic, no longer deformed by those images, Cancer, Taurus, Leo, Sagittarius, but beaming with the mild radiance of those heavenly signs, Faith, Hope, and Charity.