The author of a piece entitled "Why Quakerism is not a soft option" writes:

These days, through living in a multi-cultural world we are much more aware that an experience of God cannot be confined to one particular religion.

This sentiment is expressed in various contexts and in various ways throughout the Quaker realm and outside of it. I understand completely the want to expose the lacking of the various religions based upon the religious reasonings of men and woman and the outward institutional structures built to frame and support ideological constructs and belief systems. 

While it is true these religions fall short in their attempts to confine and define (through natural faculties) the experience of Presence, it is equally true that the experience of Presence is the true Religion ... the true Voice of God. The true Religion is not conceptual or intellectual. It is experiential. When consciousness and conscience are filled with eternal Presence, the ideological, theoretical, theological, and mental frameworks of religions are shattered and fail in the light of Immutable. 

Many people falsely read into the early Quakers the desire to set up another religion ... a "true religion" ... to take the place of those in apostasy. This is a complete misrepresentation of the early quaker testimony and that of those who share their experience today. The power of the early Quaker testimony is that while these various abstract religions of the minds of men and women are insufficient, there is direct experience of Presence and this non-conceptual, this non-abstract experience is true Religion. 

Penington writes:

It is not enough to be rent from Popery, and sit down under the power and government of the same spirit in an other form; or to be rent from Episcopacy, and the same spirit sit down in Presbytery; or to be rent from Presbytery, and the same spirit sit down in a form of Independency, or Anabaptism ; or to be rent from these, and the same spirit sit down in a way of seeking and waiting, and reading of words of scripture, and gathering things from thence without the life: but  the true religion consists in knowing and following a true guide to the church in the wilderness, and thereto receive the mark, the living mark, which will preserve out of all invention, and further progress of the dead spirit.

The Works of Penington - Volume Three - page 320

https://play.google.com/books/reader?printsec=frontcover&output...

 It is not enough to point to the lacking in various religions. We must bear the burden even further and affirm the true Religion, the true life that transcends and makes irrelevant all religions and all ways and practice. The true Religion is a direct experience of the eternal Presence within. Presence is Religion. The true Religion is experienced, it is the experience of eternal consciousness and pure conscience in all things and in all circumstances in this life. This experience is sufficient in itself. It is the minds of men and women free from abstract institutional frameworks and the reasonings of those within them.

For I also did believe and expect great things in a church-state and way of worship; and in simplicity of heart did I enter into it, and walk in it, and was not without knowledge, warmth, and experiences there. But all this the Lord broke down by a strong hand, in one moment; and hath taught me since to throw away all my gains here, and elsewhere, and to count them but dross and dung, for the excellency of the knowledge of Jesus Christ my Lord. And having tasted, having seen, having felt, having handled, I cannot but commend the life ; and dissuade all men from all knowledge, all worship, all religion, all ways, and practices (though ever so taking, pleasant, and promising), out of the life. And this is to know Christ; namely, to know the life: and this is to obey Christ, to obey the life: and this is the kingdom of Christ which is to come, to have the life reign in power and great glory. But the knowing or believing of a history concerning Christ, this is not the knowledge or the faith: antichrist all along the apostasy, in all his various forms and dresses, hath known and believed thus: and this kind of knowledge must pass away, further  than it can find a place and service in the life.

Source: The works of Isaac Penington - Volume One - Page 241

https://play.google.com/books/reader?id=bocBHRjRH1MC&printsec=f...

This quote is pivotal to understanding the early Quaker testimony of the true Religion. How can Penington write:

And having tasted, having seen, having felt, having handled, I cannot but commend the life ; and dissuade all men from all knowledge, all worship, all religion, all ways, and practices (though ever so taking, pleasant, and promising), out of the life.

and at the same time profess a true Religion? Because the Religion of which he speaks is known and experienced by individuals caught up in the various religions of man. The Life, the Presence, unconfined by the religions of man is the true Religion that is sufficient in itself. 

I invite you to read all of Penington's uses of the phrase "true Religion" from The Works of Isaac Penington and experience life transformed by the true Religion. I've collected them in these four pages below referenced by Volume and page number with links to the actual source I drew them from in google books:

From Volume One:

https://docs.google.com/document/d/1-SziZlcuxkZQ4HK936oYHP1OUU0ez8P...

From Volume Two:

https://docs.google.com/document/d/14t1JdbJY-lr4QtHQg6ss9DMXrREqkIO...

From Volume Three:

https://docs.google.com/document/d/16-3WMVhfmIhwwJFtc069rVgzdJzkqhA...

From Volume Four:

https://docs.google.com/document/d/16Ry9C8KZ-Jx7KmmEqM56PoZ9xAME13v...

This deep study, when read in context, is a powerful affirmation of the true Religion open to everyone, anywhere, in every social context, and in all circumstances. It is such a blessing to know and share the true Religion testified to by the early Quakers; to know the Life and experience of the transformation and renewal of the mind through the mystery of a consciousness anchored in and a conscience informed by the inwardly Presence ... the true Religion.

A Labor of Love ... Keith