Protestantism/ the Reformation
And the eye cannot say to the hand: I need not thy help; nor again the head to the feet: I have no need of you. Yea, much more those that seem to be the more feeble members of the body, are more necessary. And such as we think to be the less honourable members of the body, about these we put more abundant honour; and those that are our uncomely parts, have more abundant comeliness. But our comely parts have no need: but God hath tempered the body together, giving to that which wanted the more abundant honour, That there might be no schism in the body; but the members might be mutually careful one for another. And if one member suffer any thing, all the members suffer with it; or if one member glory, all the members rejoice with it.
~1 Corinthians 12:21-26
From the beginning, this one Church has been marked by a great diversity which comes from both the variety of God's gifts and the diversity of those who receive them. Within the unity of the People of God, a multiplicity of peoples and cultures is gathered together. Among the Church's members, there are different gifts, offices, conditions, and ways of life. "Holding a rightful place in the communion of the Church there are also particular Churches that retain their own traditions." The great richness of such diversity is not opposed to the Church's unity. Yet sin and the burden of its consequences constantly threaten the gift of unity. And so the Apostle has to exhort Christians to "maintain the unity of the Spirit in the bond of peace."
~Catechism of the Catholic Church, Paragraph 814
Ecclesial communities derived from the Reformation and separated from the Catholic Church, "have not preserved the proper reality of the Eucharistic mystery in its fullness, especially because of the absence of the sacrament of Holy Orders." It is for this reason that, for the Catholic Church, Eucharistic intercommunion with these communities is not possible. However these ecclesial communities, "when they commemorate the Lord's death and resurrection in the Holy Supper . . . profess that it signifies life in communion with Christ and await his coming in glory."