While studying with Jonathan Edwards at his home in Northampton Samuel Hopkins decided to become a preacher. Edwards' influence in Hopkins' doctrines is readily apparent, but Edwards' preaching style apparently had no effect on Hopkins' delivery. Though his sermons were filled with new ideas and profound truths that his congregations seized upon, his preaching style was horrible. W.E. Channing once said about his speaking style: "He was the very ideal of bad delivery; such tones never came from any human voice within my hearing" (Walker, 325). Hopkins himself was aware of shortcomings in the pulpit, to the point that he often considered removing himself from his position as a minister permanently. His decision to remain in the pulpit led to a theological life filled with powerful discourses and significant ideas. Four of his most controversial writings were, An Inquiry into the Nature of true Holiness; Sin, `thro Divine Interposition, an Advantage to the Universe; and yet, this is no Excuse for Sin, or Encouragement to it; An Enquiry Concerning the Promises of the Gospel, whether any of them are made to the Exercises and Doings of persons in an Unregenerate State; and A Treatise on the Millennium. These four works put forth the three most significant and basic parts of his theology: benevolence, sin, and the millennium.Hopkins based most of his ideas on the Edwardean belief that "the Holiness of God primarily consists in LOVE, or benevolence to himself, and to the Creature" (Walker, 330). Since God is benevolent, he does things for the good of the whole and the individual become less important. In doing so, righteousness is spread and God's glory is amplified. All men are called to live their lives as perfect examples of this virtue. To be such, man must become completely disinterested in himself or his fate and do everything for the glory of God. This principle led to one of Hopkins' most famous views, the "willingness to be damned" concept. To Hopkins, one must become so distinterested in his fate that he must be perfectly willing to be damned for the glory of God, even if it is an unfair fate. When one has reached this point, he has achieved holiness and can be assured of salvation. This view, like many of his to follow, led to numerous debates with his colleagues in the New England ministerial world.
Another key idea derived from this notion of benevolence was that sin is caused by self-love, or a lack of benevolence. This self-love reflects an intrinsic "bias" in man towards sin that leads him into evil. In this way, Hopkins solved a prominent problem in Calvinist doctrine: "If God is the author of all things, is he the author of sin?"; with his notion of "bias" he shows that man is responsible for his sin, not God. God only is responsible for the changing of that evil bias into a bias towards righteouseness, which is accomplished solely by the Holy Spirit through regeneration. However, this notion of regeneration leads to another controversial view held by Hopkins. Hopkins argues that those who are definitely regenerate should attend church and receive Christian instruction. Those who are not regenerate, however, should not do anything of the sort because their lack of repentance is sinful. By not repenting of their sins and converting though they hear the Gospel in church and teachings, the unregenerate are sinning greatly against God and his benevolence. To Hopkins, a morally upright unregenerate man who attends church but has not repented of his sin is more sinful than an evil man who openly scorns religion. This harsh view of sin led to many sharp replies by his contemporaries.
Hopkins' notion of sin also relies on the view that sin is in the universe because it always yields goodness through God's benevolence. To Hopkins, God transforms the initial evil wrought by sin into an eventual good through interacting in man's earthly life. Hopkins' intense patriotism and this view of God's providence and sovereignty combined to produce yet another unpopular belief of his: the belief that slavery is wrong. He argued that slavery is wrong for two reasons: first, it goes against America's principle of "freedom for all;" second, it is an unbenevolent institution. Yet, according to Hopkins' view of sin, slavery does have a silver lining - the evangelization of Africa through the introduction of missionaries into the continent through the channels set by the slave market. All of this led Hopkins to become active in abolitionist circles, even to the point of selling his slave and donating the money he received for him towards abolitionist causes. He succeeded in sending several missionaries to Africa, but incurred the wrath of many wealthy Puritans who held slaves themselves.
The goodness of sin, Hopkins argued, is proved through the events of human history in which we know that God played a role: the slavery of the Israelites in Egypt, the Babylonian captivity, and the Crucifixion itself, for example. This emphasis on God's intervention in human history led to Hopkins' favorite topic, the coming millennium. Unlike his contemporaries, Hopkins loved to think about the events preceding and during the time to come, not the attributes of the millennial reign itself. He devoted much of his time to exploring the books of Daniel and Revelation in search of any new clues to the nature of the coming world. He took a particularly un-Calvinistic position when he preached that thousands of people would be saved with the arrival of the millennium, though many of his contemporaries were preaching the opposite. All of these thoughts about the millennium led him dedicate a whole treatise, Millennium, to the subject and let his imagination run wild when reasoning about this period of time. One particularly interesting notion he had was that during the millennial reign, "men would rediscover how to move big stones to great heights (just as the Egyptians had done with the pyramids)" (Davidson, 271).
In conclusion, Hopkins work had far-reaching effects on American religious life. With the arrival of his ideas concerning the sinfulness of unregenerates, his colleague Jedediah Mills called the doctrine a "new divinity" as a term of reproach for what he deemed was an unacceptable Calvinist belief. However, as time went on, this term was formalized and began to refer to the systems of belief put forth by Hopkins, Edwards' other student Joseph Bellamy, and any other preachers whose thoughts concurred with theirs. After numerous influential sermons and treatises, Hopkins's final and most powerful work was published in 1793: System of Doctrines, Contained in Divine Revelation, explained and defended. This piece tied together all of the above views into a coherent system dubbed "Hopkinsianism," sold over 1200 copies, and had a great effect on New England theology: 40 years after its publication, over 100 Congregationalist preachers had adopted Hopkins' views as their own. Hopkins views became the basis for a very important series of American revivals between 1791 and 1858, helped spark Puritans to follow the abolitionist cause, and generally gave the Congregationalist world a deeper and richer understanding of Edwardsean theology and its logical derivatives.