John Wesley on faith:
From “On Faith”
But what is Faith? It is a divine “evidence and conviction of things not seen;” of things which are not seen now, whether they are visible or invisible in their own nature. Particularly, it is a divine evidence and conviction of God, and of the things of God. This is the most comprehensive definition of faith that ever was or can be given; as including every species of faith, from the lowest to the highest.
But what is the faith which is properly saving; which brings eternal salvation to all those that keep it to the end? It is such a divine conviction of God, and the things of God, as, even in its infant state, enables every one that possesses it to “fear God and work righteousness.” And whosoever, in every nation, believes thus far, the Apostle declares, is “accepted of him.” He actually is, at that very moment, in a state of acceptance. But he is at present only a servant of God, not properly a son. Meantime, let it be well observed, that “the wrath of God” no longer “abideth on him.”
From “Salvation by Faith”
Christian faith is then, not only an assent to the whole gospel of Christ, but also a full reliance on the blood of Christ; a trust in the merits of his life, death, and resurrection; a recumbency upon him as our atonement and our life, as given for us, and living in us; and, in consequence hereof, a closing with him, and cleaving to him, as our “wisdom, righteousness, sanctification, and redemption,” or, in one word, our salvation.
From “Justification by Faith”
Faith in general is a divine, supernatural “elegchos,” “evidence” or “conviction,” “of things not seen,” not discoverable by our bodily senses, as being either past, future, or spiritual. Justifying faith implies, not only a divine evidence or conviction that “God was in Christ, reconciling the world unto himself;” but a sure trust and confidence that Christ died for “my” sins, that he loved “me,” and gave himself for “me.” And at what time soever a sinner thus believes, be it in early childhood, in the strength of his years, or when he is old and hoary-haired, God justifieth that ungodly one: God, for the sake of his Son, pardoneth and absolveth him, who had in him, till then, no good thing. Repentance, indeed, God had given him before; but that repentance was neither more nor less than a deep sense of the want of all good, and the presence of all evil. And whatever good he hath, or doeth, from that hour when he first believes in God through Christ, faith does not “find,” but “bring.” This is the fruit of faith. First the tree is good, and then the fruit is good also.