#20: The Gospel and Its Influence - Christian Resource Centre (Bermuda)

The covenant of works being broken by sin, and made unprofitable for life, God was pleased to promise Christ, the seed of the woman, as the means of calling the elect and bringing to life within them faith and repentance. In this promise the substance of the Gospel was revealed and shown to be the effectual for the conversion and salvation of sinners.
This promise of Christ and the salvation which comes by Him, is revealed only by the Word of God. The works of creation and providence with the light of nature do not reveal Christ or His grace even in a general or obscure way. How much less, therefore, can those who are devoid of the revelation of Christ by the promise (or the Gospel) be enabled by the light of nature to arrive at saving faith or repentance.
The revelation of the Gospel unto sinners, made in divers times and by sundry parts, with the addition of promises and precepts for the obedience required therein, as to the nations and persons to whom it is granted, is merely of the sovereign will and good pleasure of God, not being annexed by virtue of any promise to the due improvement of men's natural abilities, by virtue of common light received without it, which none ever did make, or can do so; and therefore in all ages, the preaching of the Gospel has been granted unto persons and nations, as to the extent or straitening of it, in great variety, according to the counsel of the will of God.
Although the Gospel is the only outward means of revealing Christ and saving grace, and as such is totally sufficient to accomplish this, yet more is necessary if men who are dead in trespasses are to be born again, brought to life or regenerated. It is necessary for there to be an effectual, insuperable work of the Holy Spirit upon the whole soul to produce in them a new spiritual life. Without this no other means will bring about their conversion to God.