“The Second Great Awakening led to the end of slavery.”
No. The Civil War ended slavery (3 million slaves) with the loss of 720,000 soldiers—not counting the tens of thousands of civilians killed in the South)— and that war was orchestrated by very irreligious men.
Both are true. The SGA led to the peaceful elimination of slavery in the British Empire, largely due to William Wilberforce.
In the US, it led to the recognition, by those who either converted or deepened their faith, that under Christ all people were equal and should be equally free. One of the effects of this was the formation of the Republican Party, to do what the Whigs were unwilling to do, which was to push for emancipation. Since a portion of the country refused to recognize this, the partition and civil war came about. While the issue of slavery was a frontispiece of both sides' intransigence, the war like most wars took on a life of its own, where forcing the other side to surrender became the primary consideration, and that takes a Joab or a Jehu, rather than a Moses or a David.
However,
Although many Enlightenment philosophers opposed slavery, it was Christian activists, attracted by strong religious elements, who initiated and organized an abolitionist movement. [1] Throughout Europe and the United States, Christians, usually from 'un-institutional' Christian faith movements, not directly connected with traditional state churches, or "non-conformist" believers within established churches, were to be found at the forefront of the abolitionist movements.[1][2]
In particular, the effects of the Second Great Awakening resulted in many evangelicals working to see the theoretical Christian view, that all people are essentially equal, made more of a practical reality. Freedom of expression within the Western world also helped in enabling opportunity to express their position. Prominent among these abolitionists was Parliamentarian William Wilberforce in England, who wrote in his diary when he was 28 that, "God Almighty has set before me two great objects, the suppression of the Slave Trade and Reformation of Morals."[3] With others he labored, despite determined opposition, to finally abolish the British slave trade. English preacher Charles Spurgeon had some of his sermons burned in America due to his censure of slavery, calling it "the foulest blot" and which "may have to be washed out in blood."[4] Methodist founder John Wesley denounced human bondage as "the sum of all villainies," and detailed its abuses.[5] In Georgia, primitive Methodists united with brethren elsewhere in condemning slavery. Many evangelical leaders in the United States such as Presbyterian Charles Finney and Theodore Weld, and women such as Harriet Beecher Stowe (daughter of abolitionist Lyman Beecher) and Sojourner Truth motivated hearers to support abolition. Finney preached that slavery was a moral sin, and so supported its elimination. "I had made up my mind on the question of slavery, and was exceedingly anxious to arouse public attention to the subject. In my prayers and preaching, I so often alluded to slavery, and denounced it.[6] Repentance from slavery was required of souls, once enlightened of the subject, while continued support of the system incurred "the greatest guilt" upon them.[7]
Quakers in particular were early leaders in abolitionism. In 1688 Dutch Quakers in Germantown, Pennsylvania, sent an antislavery petition to the Monthly Meeting of Quakers. By 1727 British Quakers had expressed their official disapproval of the slave trade.[8] Three Quaker abolitionists, Benjamin Lay, John Woolman, and Anthony Benezet, devoted their lives to the abolitionist effort from the 1730s to the 1760s, with Lay founding the Negro School in 1770, which would serve more than 250 pupils.[9] In June 1783 a petition from the London Yearly Meeting and signed by over 300 Quakers was presented to Parliament protesting the slave trade.[10]
In 1787 the Society for Effecting the Abolition of the Slave Trade was formed, with 9 of the 12 founder members being Quakers. During the same year, William Wilberforce was persuaded to take up their cause; as an MP, Wilberforce was able to introduce a bill to abolish the slave trade. Wilberforce first attempted to abolish the trade in 1791, but could only muster half the necessary votes; however, after transferring his support to the Whigs, it became an election issue. Abolitionist pressure had changed popular opinion, and in the 1806 election enough abolitionists entered parliament for Wilberforce to be able to see the passing of the Slave Trade Act 1807. The Royal Navy subsequently declared that the slave trade was equal to piracy, the West Africa Squadron choosing to seize ships involved in the transfer of slaves and liberate the slaves on board, effectively crippling the transatlantic trade. Through abolitionist efforts, popular opinion continued to mount against slavery, and in 1833 slavery itself was outlawed throughout the British Empire – at that time containing roughly 1/6 of the world's population (rising to 1/4 towards the end of the century). - https://en.wikipedia.org/wiki/Christian_Abolitionism