Book of Common Prayer (page 877)

4. That this Church does not seek to absorb other Communions, but
rather, co-operating with them on the basis of a common Faith and Order,
to discountenance schism, to heal the wounds of the Body of Christ, and
to promote the charity which is the chief of Christian graces and the
visibile manifestation of Christ to the world.

But furthermore, we do hereby affirm that the Christian unity...can be
restored only by the return of all Christian communions to the
principles of unity exemplified by the undivided Catholic Church during
the first ages of its existence; which principles we believe to be the
substantial deposit of Christian Faith and Order committed by Christ and
his Apostles to the Church unto the end of the world, and therefore
incapable of compromise or surrender by those who have been ordained to
be its stewards and trustees for the common and equal benefit of all
men.

As inherent parts of this sacred deposit, and therefore as essential to
the restoration of unity among the divided branches of Christendom, we
account the following, to wit:

1. The Holy Scriptures of the Old and New Testaments as the revealed
Word of God.

2. The Nicene Creed as the sufficient statement of the Christian Faith.

3. The two Sacraments,--Baptism and the Supper of the Lord,--ministered
with unfailing use of Christ's words of institution and of the elements
ordained by Him.

4. The Historic Episcopate, locally adapted in the methods of its
administration to the varying needs of the nations and peoples called of
God into the unity of His Church.

Furthermore, Deeply grieved by the sad divisions which affect the
Christian Church in oun own land, we hereby declare our desire and
readiness, so soon as there shall be any authorized response to this
Declaration, to enter into brotherly conference with all or any
Christian Bodies seeking the restoration of the organic unity of the
Church, with a view to the earnest study of the conditions under which
so priceless a blessing might happily be brought to pass.

Note: While the above form of the Quadrilateral was adopted by the
House of Bishops, it was not enacted by the House of Deputies, but
rather incorporated in a general plan referred for study and action to a
newly created Joint Commission on Christian Reunion.

Lambeth Conferent of 1888
Resolution 11

That, in the opinion of this Conference, the following Articles supply a
basis on which approach may be by God's blessing made towards Home
Reunion:

(a) The Holy Scriptures of the Old and New Testaments, as "containing
all things necessary to salvation," and as being the rule and ultimate
standard of faith.

(b) The Apostles' Creed, as the Baptismal Symbol; and the Nicene Creed,
as the sufficient statement of the Christian faith.