The great prophets themselves did not accept this language of other prophets unquestioningly. They denied the claim unhesitatingly when satisfied that the messages were not from on high. They distinguished between those who came in the name of the Lord; and so must we. They tried the spirits whether they were of God; bidding us therefore do the same. Tried by the severest scrutiny of successive centuries, of different races, the great prophets prove to have spoken truly when they declared, of their ethical and spiritual messages, "Thus saith the Lord." If ever messages from on high have come to men, if ever the Spirit of God has spoken in the spirit of man, it was in the minds of these "men of the spirit." But they made no claim to infallibility, or if they did, took pains to disprove it. Every prophet who goes beyond ethical and religious instruction, and ventures into predictions, makes mistakes, and leaves his errors recorded for our warning. We must try even the inspired men, and when, overstepping their limitations, they err, we must say, Thus saith Isaiah, Thus saith Jeremiah. No biblical writer shows any consciousness of such supernatural influences upon him in his work as insured its infallibility. Nearly all these authors begin and end their books without any reference to themselves or their work. The writer of the Gospel according to Luke thus prefaces his book: "Forasmuch as many have taken in hand to draw up a narrative concerning those matters which have been fulfilled among us, even as they delivered them unto us which from the beginning were eye-witnesses and ministers of the word, it seemed good to me also, having traced the course of all things accurately from the first, to write unto thee in order, most excellent Theophilus, that thou mightest know the certainty concerning the things which thou wast taught by word of mouth." This is the only personal preface to any of the Gospels, and it is thoroughly human. There is not even such an invocation as introduces Milton's great poem. These writers at times, after the fashion of the older prophets, affirm that they speak with divine authority; but they also as expressly disclaim such authority in other places. St. Paul is sure, in one matter referred to him, of the mind of God, and writes: "Unto the married I command, yet not I, but the Lord," etc.[2] Immediately after he writes, as having no such assurance: "To the rest speak I, not the Lord."[3] Later on in the same letter he is so uncertain as to add to his judgment: "And I think also that I have the spirit of God."[4] Again, in the same connection, being conscious of no divine authorization, he gives his own opinion as such: "Now, concerning virgins I have no commandment of the Lord, but I give my judgment."[5]