(1.) Some important article of revealed religion must be proposed to be believed; and in order thereunto, an explicit appeal made to God, in expectation of his immediate interposure in working a miracle for that end: every thing that was the object of faith, was not, indeed, to be proved true by a miracle, but only those things which could not be sufficiently evinced without it, so as to beget a divine faith in those who were the subjects of conviction. We never read that miracles were wrought to convince the world that there was a God, or a providence; or, to persuade men concerning the truth of those things that might be sufficiently proved by rational arguments: but when there could not be such a proof given without the finger of God being rendered visible by a miracle wrought, then they depended on such an instance of divine condescension; and the people who were to receive conviction, were to expect such an extraordinary event. (2.) It was necessary that there should be a firm persuasion of the truth of the doctrine, to be confirmed by a miracle in him that wrought it, together with an explicit appeal to it for the conviction of those whose faith was to be confirmed thereby: and sometimes we read, that when miracles were to be wrought in favour of them, who before had a sufficient proof that our Saviour was the Messiah, it was necessary that they should have a strong persuasion concerning this matter, and that he was able to work a miracle; otherwise they had no ground to expect that the miracle should be wrought: in the former instance we read of Christ’s disciples working miracles for the conviction of the Jews, and exercising, at the same time, this faith of miracles; and in the latter a general faith was demanded, that our Saviour was the Messiah, before the miracle was wrought; in which sense we are to understand his reply to the man who desired that he would cast the Devil out of his son; _If thou canst believe, all things are possible to him that believeth_, Mark ix. 23. _q. d._ Thou hast had sufficient conviction that I am the Messiah, by other miracles, and consequently hast no reason to doubt but that I can cast the Devil out of thy son; therefore, if thou hast a strong persuasion of the truth hereof, the thing that thou desirest shall be granted: and elsewhere it is said, _He did not many mighty works because of their unbelief_, Matt. xiii. 58.