Revelation old and new

IV. The authority of the Holy Scripture, for which it ought to be believed, and obeyed, depends not upon the testimony of any man, or Church; but wholly upon God (who is truth itself) the author thereof: and therefore it is to be received, because it is the Word of God.

V. We may be moved and induced by the testimony of the Church to an high and reverent esteem of the Holy Scripture. And the heavenliness of the matter, the efficacy of the doctrine, the majesty of the style, the consent of all the parts, the scope of the whole (which is, to give all glory to God), the full discovery it makes of the only way of man's salvation, the many other incomparable excellencies, and the entire perfection thereof, are arguments whereby it does abundantly evidence itself to be the Word of God: yet notwithstanding, our full persuasion and assurance of the infallible truth and divine authority thereof, is from the inward work of the Holy Spirit bearing witness by and with the Word in our hearts.

VI. The whole counsel of God concerning all things necessary for His own glory, man's salvation, faith and life, is either expressly set down in Scripture, or by good and necessary consequence may be deduced from Scripture: unto which nothing at any time is to be added, whether by new revelations of the Spirit, or traditions of men. Nevertheless, we acknowledge the inward illumination of the Spirit of God to be necessary for the saving understanding of such things as are revealed in the Word: and that there are some circumstances concerning the worship of God, and government of the Church, common to human actions and societies, which are to be ordered by the light of nature, and Christian prudence, according to the general rules of the Word, which are always to be observed....

X. The supreme judge by which all controversies of religion are to be determined, and all decrees of councils, opinions of ancient writers, doctrines of men, and private spirits, are to be examined, and in whose sentence we are to rest, can be no other but the Holy Spirit speaking in the Scripture. [Emphasis added.]

The citation for the claim of those former ways of God's revealing His will unto His people being now ceased is Hebrews 1:1-2:

God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets, hath in these last days spoken unto us by his Son, whom he hath appointed heir of all things, by whom also he made the worlds;

Fox himself used this quote on a regular basis to discuss Christ's presence, and there is nothing here that states clearly that God no longer speaks except through Scripture. The Spirit in this confession is accepted only as a means by which we may come into accordance with Scripture, and that within the narrowest bounds possible. Compounding that, the Scripture is treated as the exclusive Word of God, which is difficult to square with John 1:1:

In the beginning was the Word, and the Word was with God, and the Word was God.

While I find this Confession hard to square with the Scripture it exalts, that obviously hasn't been a problem for many people, then and now. The Protestant Reformers, in abandoning the authority of the Church and Tradition, felt bound to look somewhere else for authority, and found their foundation in Scripture. Building on the Spirit no doubt felt - as it usually has - too risky, too prone to false claims of inspiration and too open to conflict. (The Spirit's role in salvation led these same people toward predestination, rather than to a powerful God interacting with the people he had created and supposedly left free.)

Quakerism leapt on the notion that the Spirit still speaks, and that "there is one, even Christ Jesus, that can speak to thy condition." While Fox was so immersed in the Bible that many of his writings are uncited quotations, Christ's presence was very real to him, not something used exclusively to demonstrate the divinity of the Bible. The Spirit's role in interpreting the Bible was critical to Fox, but that was far from the only function of the Spirit, as this 1653 letter demonstrates:

XLII. - To Friends, concerning the light, in which they may see their saviour, and the deceivers.

To all Friends every where, scattered abroad: in the light dwell which comes from Christ, that with it ye may see Christ your saviour; that ye may grow up in him. For they who are in him are new creatures, and 'old things are passed away, and all things are become new.' And who are in him, are led by the spirit, to them there is no condemnation; but they dwell in that which doth condemn the world, and with the light see the deceivers, and the antichrists, which are entered into the world..

And such teachers as bear rule by their means; and such as seek for the fleece, and make a prey upon the people, and are hirelings, and such as go in the way of Cain, and run greedily after the error of Balaam; and such as are called of men master, and stand praying in the synagogues, and have the chief seats in the assemblies, all which are in the world, who by those that dwelt in the light, were cried against; for it did them condemn, and all such as speak a divination of their own brain, and are filthy dreamers, who use their tongues, and steal the words from their neighbours; with the light, the wolrd and all these aforesaid are comprehended, and all that is in it; all they that hate it, and all the antichrists that oppose it, and all the false prophets and deceivers, that are turned from it, with the light are comprehended, and with the light are condemned, and all that are turned from it and hate it.

'I am the light of the world,' saith Christ, and he doth enlighten everyone that cometh into the world; and he that loves the light, and walks in the light, receives the light of life: and the other, he hates the light, because his deeds are evil, and the light doth reprove him. And this is the condemnation, that light is come into the world, in which light, they that love it, walk; which is the condemnation of him that hates it....

For he is not an antichrist, that walks in the light that comes from Christ; he is no deceiver that walks in the light that comes from Christ. Many deceivers are entered into the world. The world hates the light, and deceivers are turned from the light, and the antichrists they are turned from the light, therefore they oppose it, and some of them call it a natural conscience, a natural light; and such put the letter for the light.

But with the light, which never changes, (which was before the world was,) are these deceivers seen, when they enter into the world.... And here it is not possible, that they that dwell in the light should be deceived, which comprehends the world, and is the world's condemnation. Which light shall bring every tongue to confess, and every knee to bow: when the judgements of God come upon them, it shall make them confess, that the judgments of God are just. (Works, VII, p. 50-1, emphasis and paragraph breaks added.)

The Spirit, the light, is strong for Fox, coming from Christ, originating before the world, and not a mere natural light of human reason. It is not only a guide to the Scriptures, but a path to walk in or to hate. The Spirit interacts with us constantly, and the 'elect' here are those who can best discern the path in the Spirit's light.

Fox would, of course, later have to deal with the consequences of such a direct connection, lacking the simple appeal to scripture as a path for discipline. The notion that the light never changes yet is available to all is the means by which "such as speak a divination of their own brain" can be revealed, allowing the construction of a firmer base to build Quakerism than its Puritan critics imagined possible.

Update: This Wikipedia article on cessationism has more on the question of whether "those former ways of God's revealing His will unto His people being now ceased" makes sense.