The antislavery agitation was now beginning, and into this he threw himself with all the ardor of his nature. He became the poet of the reform as Garrison was its apostle, and Sumner and Phillips its speakers. In 1833 he published _Justice and Expediency_, a prose tract against slavery, and in the same year he took part in the formation of the American Antislavery Society at Philadelphia, sitting in the convention as a delegate of the Boston abolitionists. Whittier was a Quaker, and that denomination, influenced by the preaching of John Woolman and others, had long since quietly abolished slavery within its own communion. The Quakers of Philadelphia and elsewhere took an earnest though peaceful part in the Garrisonian movement. But it was a strange irony of fate that had made the fiery-hearted Whittier a friend. His poems against slavery and disunion have the martial ring of a Tyrtaeus or a Körner, added to the stern religious zeal of Cromwell's Ironsides. They are like the sound of the trumpet blown before the walls of Jericho, or the psalms of David denouncing woe upon the enemies of God's chosen people. If there is any purely Puritan strain in American poetry it is in the war-hymns of the Quaker "Hermit of Amesbury." Of these patriotic poems there were three principal collections: _Voices of Freedom_, 1849; _The Panorama, and Other Poems_, 1856; and _In War Time_, 1863. Whittier's work as the poet of freedom was done when, on hearing the bells ring for the passage of the constitutional amendment abolishing slavery, he wrote his splendid _Laus Deo_, thrilling with the ancient Hebrew spirit:
"Loud and long Lift the old exulting song, Sing with Miriam by the sea-- He has cast the mighty down, Horse and rider sink and drown, He hath triumphed gloriously."
Of his poems distinctly relating to the events of the civil war, the best, or at all events the most popular, is _Barbara Frietchie_. _Ichabod_, expressing the indignation of the Free Soilers at Daniel Webster's seventh of March speech in defense of the Fugitive Slave Law, is one of Whittier's best political poems, and not altogether unworthy of comparison with Browning's _Lost Leader_. The language of Whittier's warlike lyrics is biblical, and many of his purely devotional pieces are religious poetry of a high order and have been included in numerous collections of hymns. Of his songs of faith and doubt, the best are perhaps _Our Master_, _Chapel of the Hermits_, and _Eternal Goodness_; one stanza from the last of which is familiar;