The Sabbath is, in some respects, the great, the cheering hope of the human race. It is emphatically the day of the poor, the suffering, the enslaved, the prisoner. Without it, the poor man would scarcely have hope; laboring, as he would then be obliged to do, without cessation, and yet without additional emolument; — the slave, who experiences rest, and receives instruction on this day, would find his state of bondage more trying and distressing than ever; — the ignorant man, who greatly needs knowledge, would find many important avenues of knowledge closed to him; and the evils and sufferings which afflict our race would be, in various ways, greatly increased.
We may, perhaps, admit that the Sabbath, considered in its relations to the human race, was made for the unholy rather than for the holy. That is to say, the holy man, who has a perpetual Sabbath in his soul, could, perhaps, do without it, while the unholy man could not. But then it is to be remembered, that no man can properly be regarded as a truly religious or holy person, who has not a disposition to cooperate with God. Our great business is, to stand in union with him, who here and everywhere unfolds our destiny. If, therefore, it is the design of God to benefit men, especially the degraded and the sinful, through the medium of the Sabbath, it is justly expected of all who regard God's will and are like him, that they will observe and honor the Sabbath day. They cannot be united with him in spirit, without being united with him in the observance of this important institution; sympathizing in its objects, fulfilling its duties, and rejoicing in the hopes it inspires.
— edited from A Treatise on Divine Union (1851) Part 7, Chapter 5.