The Religion of Christ is the Absolute Religion

The religion of Christ, which is only another name for the principles involved in the teachings of Christ, is the Absolute Religion; because having incarnated itself in Christ and thus shown its divine beauty in the human form, it henceforth belongs to man, not perhaps in the temporary and changing incidents of his history, but to man in his essential and universal nature, and therefore is the religion of humanity. The religion of Christ is the Absolute Religion because, though it may be said in its personal applications to grow up and to put forth the buds and flowers of feeling, the rich and beautiful experiences of emotions and affections, it nevertheless has its root in the deepest thought, and is both grounded in, and harmonizes with, unchangeable intuitions. The religion of Christ is the Absolute Religion, though man is its object, and is also, in the exercise of his powers of perception and reasoning, the appointed and necessary instrument of its development, yet being founded in the nature and constitution of things, and thus being beyond measurements of time, it synchronizes with God himself in its origin and continuance, and goes step by step with the divine authority in the assertion of its universal empire.

— Absolute Religion (1873) Chapter 1.