To this I would say these things: 

1.  It is true, that “faith is the gift of God,” Eph. ii. 8, and that it is “he alone who worketh in us, both to will and to do,” Phil. i. 29, “and none cometh to the Son, but whom the Father draweth,” John vi. 44; and it is a great matter, and no small advancement, to win to the real faith, and through conviction of this our impotency.  For thereby the soul will be brought to a greater measure of humiliation, and of despairing of salvation in itself, which is no small advantage unto a poor soul that would be saved.

2.  Though faith be not in our power, yet it is our duty.  Our impotency to perform our duty, doth not loose our obligation to the duty; so that our not believing is our sin; and for this God may justly condemn us.  His wrath abideth on all who believe not in his Son Jesus, and will not accept of the offer of salvation through the crucified Mediator.  And though faith, as all other acts of grace, be efficiently the work of the Spirit, yet it is formally our work:  we do believe; but it is the Spirit that worketh faith in us.

3.  The ordinary way of the Spirit’s working faith in us, is by pressing home the duty upon us, whereby we are brought to a despairing in ourselves, and to a looking out to him, whose grace alone it is that can work it in the soul, for that necessary help and breathing, without which the soul will not come.

4.  Christ Jesus hath purchased this grace of faith to all the elect, as other graces necessary to their salvation; and it is promised and covenanted to him, “That he shall see his seed, and shall see of the travail of his soul,” Isa. liii. 10; and that by the knowledge of him, that is, the rational and understanding act of the soul gripping to and laying hold upon him, as he is offered in the gospel, “many shall be justified,” Isa. liii. 10.  Hence he saith, “That all whom the Father hath given to him, shall come unto him,” John vi. 37; and the apostle tells us, “that we are blessed with all spiritual blessings in him,” Eph. i. 3.

5.  Not only hath Christ purchased this grace of faith, and all other graces necessary for the salvation of the elect, but God hath committed to him the administration and actual dispensation, and out-giving of all those graces, which the redeemed stand in need of.  Hence “he is a prince exalted to give repentance and forgiveness of sins,” Acts v. 31.  “All power in heaven and earth is committed unto him,” Matt, xxviii. 18, 19.  Hence he is called, “the author and finisher of faith,” Heb. xii. 2; and he tells his disciples, John xiv. 13, 14, that whatever they shall ask in his name, he will do it.  He is made a Prince and a Saviour, “having all judgment committed unto him,” John v. 22; and “he is Lord of all,” Acts x. 36.  Rom. xiv. 9.