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.
C. The two Sacraments ordained by Christ himself -- Baptism and the Supper of the Lord -- ministered with unfailing use of Christ's words of Institution and of the elements ordained by Him.
D.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.
The Lambeth Quadrilateral was a reaffirmation, with changes in language but not purport, of four articles proposed in the General Convention of the Protestant Episcopal Church, meeting in Chicago, 1886  , in response to a thousand requests from clergymen bearing on 'the restoration of Christian unity.' The Convention declared it to be
(1) their earnest desire that the Saviour's prayer 'that they all may be one' may in the deepest and truest sense be speedily fulfilled; (2) we believe that all who have been duly baptized with water in the name of the Father and of the Son and of the Holy Ghost are members of the Holy Catholic Church; (3) that in all things of human ordering or human choice relating to modes of worship and discipline, or traditional customs, this Church is ready in the spirit of love and humility, to forego all preferences of her own; (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, 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 visible manifestation of Christ to the world. But furthermore we do affirm that the Christian unity so earnestly desired by the memorialists 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 age 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.
At the Lambeth Conference of 1920, Church reunion was the prominent subject of discussion and an impressive invitation to such union, called An Appeal to all Christian People, was sent forth by its members -- 'the archbishops and bishops of the Holy Catholic Church in full communion with the Church of England.' The document opened with a recognition 'of all those who believe in our Lord Jesus Christ and have been baptized into the name of the Holy Trinity, as sharing with them membership in the universal Church of Christ which is His body.' The bishops then proceeded to say that they believed that God wills fellowship and that 'it is God's purpose to manifest this fellowship, so far as this world is concerned, in an outward, visible, and united society, holding one faith, having its own recognized officers, using God-given means of grace, and inspiring all its members to the world-wide service of the Kingdom of God. This is what we mean by the Catholic Church.' Then, after referring to the ancient episcopal Communions in East and West to whom 'the Anglican Communion is bound by many ties of common faith and tradition,' they addressed 'the great non-episcopal Communions standing for rich elements of truth, liberty and life which otherwise might have been obscured or neglected, with whom we are closely linked by many affinities, racial, historical and spiritual.' Expressing the judgment that 'none can doubt that self-will, ambition, and lack of charity among Christians have been the principal factors in the mingled process of division, and that these, together with the blindness to the sin of disunion, are still mainly responsible for the breaches of Christendom,' they confessed that they 'shared in the guilt of crippling the Body of Christ and hindering the activity of His Spirit.' Looking forward to a united Church in which the bodies, now separated, 'will retain much that has long been distinctive in their methods of worship and service,' the bishops affirmed that the 'visible unity of the Church will be found to involve the whole-hearted acceptance' of the following articles:
The holy Scriptures, as the record of God's revelation of Himself to man, and as being the rule and ultimate standard of faith; and the Creed commonly called Nicene, as the sufficient statement of the Christian faith, and either it or the Apostles' Creed as the Baptismal confession of belief.
The divinely instituted sacraments of Baptism and the Holy Communion, as expressing for all the corporate life of the whole fellowship in and with Christ.
A ministry acknowledged by every part of the Church as possessing not only the inward call of the Spirit, but also the commission of Christ and the authority of the whole body.
The question is then asked, 'May we not reasonably claim that the Episcopate is the one means of providing such a ministry,' but coupled with the 'thankful acknowledgment' that the ministries of the communions not possessing the episcopate 'have been manifestly blessed and owned by the Holy Spirit as effective means of grace.' The judgment is then expressed that, in accepting episcopal ordination, 'no one could possibly be taken to repudiate his past ministry.'
 These four articles were referred to by the Lambeth Conference, 1888, as 'the important and practical step taken by our brethren of the American Church, 1886.' See Abp. Davidson: The Three Lambeth Conferences, London, 1896, 414 pp.