And as unbelief is the great characteristic of men in their original state, it may always be said with great truth, that it is natural to the human mind in that state to seek for manifestations. And this tendency, if we have formed a right estimate of it, always remains there, and continues to exert an influence, just in proportion as the mind itself remains unsanctified, either in whole or in part. It is true that man, even in his unrenewed state, often professes to regret his alienation from God, and to desire the restoration of union with him; but he first wishes to know what God is. And we are willing to acknowledge, that this is right, and is what it should be. But the difficulty is, that he seems in his unbelief, (and the same is true of the Christian just so far as unbelief remains,) to have but little reliance on any knowledge of God, which is not visible and tangible. In other words, as we have already intimated, he must have a manifestation.
It is this tendency, which explains, in part at least, some of the facts of Heathenism. In all heathen nations we find the ideas, which they entertain of their divinities, embodied in various images; which, encircled and sanctified as they are by the traditions of many generations, become to them a divine or “deific” manifestation. Behold, “these be the gods, Israel, which brought thee up out of the land of Egypt.” Their gods are before them, their Baals and Ashtaroths, their Brahmas and Vishnoos; not conceptively or as an object of the imagination, but visibly; not revealed to faith, but to sight; and they fall down and worship.
In souls, not truly and wholly consecrated to God, in other words, in souls in which faith has not become the controlling and absorbing principle, there are very likely to be some remains of this natural and unspiritual tendency. The facts of ecclesiastical history, both ancient and modern, abundantly show this to be the case. It is not enough, that God wrought miracles and sent prophets in times past, that he appeared in the clouds of Sinai, and in the burning bush of the wilderness. These things, to minds in which faith has not had its perfect work, are mere reminiscences of the past; they have become historical; they are revealed to faith, and not to sight. And hence they are looking in various directions, seeking a sign, some burning bush, some chariot of fire, some shaking of the stones of the temple and some rending of its mysterious veil, some opening in the heavens where God shall be seen visibly in a human form on a great white throne; each one, influenced by his own associations, and delineating in his own imagination the mode of his manifestation, and the time and manner of his coming.
— edited from The Life of Faith (1852) Part 2, Chapter 1.