This reference of things wonderful to God was not peculiar to the Jews. Pharaoh, on hearing the interpretation of his dream, exclaimed that the mind of the gods was in Joseph. Nebuchadnezzar told Daniel that he possessed the mind of the holy gods; so also in Latin anything well made is often said to be wrought with Divine hands, which is equivalent to the Hebrew phrase, wrought with the hand of God.
... We find that the Scriptural phrases, "The Spirit of the Lord was upon a prophet," "The Lord breathed His Spirit into men," "Men were filled with the Spirit of God, with the Holy Spirit," etc., are quite clear to us, and mean that the prophets were endowed with a peculiar and extraordinary power, and devoted themselves to piety with especial constancy; that thus they perceived the mind or the thought of God, for we have shown [elsewhere] that God's spirit signifies in Hebrew God's mind or thought, and that the law which shows His mind and thought is called His Spirit; hence that the imagination of the prophets, inasmuch as through it were revealed the decrees of God, may equally be called the mind of God, and the prophets be said to have possessed the mind of God. On our minds also the mind of God and His eternal thoughts are impressed; but this being the same for all men is less taken into account, especially by the Hebrews, who claimed a preëminence, and despised other men and other men's knowledge.
[Also] the prophets were said to possess the Spirit of God because men knew not the cause of prophetic knowledge, and in their wonder referred it with other marvels directly to the Deity, styling it Divine knowledge.
We need no longer scruple to affirm that the prophets only perceived God's revelation by the aid of imagination, that is, by words and figures either real or imaginary. We find no other means mentioned in Scripture, and therefore must not invent any. As to the particular law of Nature by which the communications took place, I confess my ignorance. I might, indeed, say as others do, that they took place by the power of God; but this would be mere trifling, and no better than explaining some unique specimen by a transcendental term. Everything takes place by the power of God. Nature herself is the power of God under another name, and our ignorance of the power of God is co-extensive with our ignorance of Nature. It is absolutely folly, therefore, to ascribe an event to the power of God when we know not its natural cause, which is the power of God.
However, we are not now inquiring into the causes of prophetic knowledge. We are only attempting, as I have said, to examine the Scriptural documents, and to draw our conclusions from them as from ultimate natural facts; the causes of the documents do not concern us.
As the prophets perceived the revelations of God by the aid of imagination, they could indisputably perceive much that is beyond the boundary of the intellect, for many more ideas can be constructed from words and figures than from the principles and notions on which the whole fabric of reasoned knowledge is reared.
Thus we have a clue to the fact that the prophets perceived nearly everything in parables and allegories, and clothed spiritual truths in bodily forms, for such is the usual method of imagination. We need no longer wonder that Scripture and the prophets speak so strangely and obscurely of God's Spirit or Mind (cf. Numbers xi. 17, 1 Kings xxii, 21, etc.), that the Lord was seen by Micah as sitting, by Daniel as an old man clothed in white, by Ezekiel as a fire, that the Holy Spirit appeared to those with Christ as a descending dove, to the apostles as fiery tongues, to Paul on his conversion as a great light. All these expressions are plainly in harmony with the current ideas of God and spirits.
Inasmuch as imagination is fleeting and inconstant, we find that the power of prophecy did not remain with a prophet for long, nor manifest itself frequently, but was very rare; manifesting itself only in a few men, and in them not often.
We must necessarily inquire how the prophets became assured of the truth of what they perceived by imagination, and not by sure mental laws; but our investigation must be confined to Scripture, for the subject is one on which we cannot acquire certain knowledge, and which we cannot explain by the immediate causes.