It is impossible that any one, with a human heart in him, can fully believe this doctrine [of hell and eternal punishment], with all the horrors it involves, with all the accusations it brings against the divine wisdom and goodness, and not feel that it is a terrible weight on his soul, and one from which he would gladly be relieved. There are many shallow minds, many flippant talkers, who find no difficulty whatever in believing, who are prompt to denounce the slightest doubt on the subject as impiety or infidelity. There are many small ministers, who are ready at a moment's notice to clear up all the difficulties of the moral and scriptural arguments; who are never embarrassed, never troubled at all in regard to the matter. But I know that the best and strongest among its believers never treat the subject in this way. Those who have looked into it most deeply and patiently, who are distinguished equally for their learning and piety, confess that, seen from any side you will, it is a fearful thing, and leads to anguish of mind, and distress of heart, and to painful questionings which cannot be answered. Can any one suppose for a moment that a doctrine, producing such mental terror and distress as this, can come from Him who said, so kindly and compassionately, "Come unto me, all ye that labor and are heavy laden, and I will give you rest. Take my yoke upon you, and learn of me; for I am meek and lowly in heart; and ye shall find rest unto your souls. For my yoke is easy, and my burden is light."? ... Besides, He expressly says that He was sent "to preach good tidings, to heal the broken-hearted, to preach deliverance to the captives, and recovering of sight to the blind, and to set at liberty them that are bruised."
-- Thomas B. Thayer, The Origin and History of the Doctrine of Endless Punishment (1855)