On Ecumenism

Ex umbris et imaginibus in veritatem

John Cardinal Newman's epitaph. ("From shades and images to the truth")

From Unitatis Redintegratio

While it is true that many Christians understand the moral teaching of the Gospel differently from Catholics, and do not accept the same solutions to the more difficult problems of modern society, nevertheless they share our desire to stand by the words of Christ as the source of Christian virtue, and to obey the command of the Apostle: "And whatever you do, in word or in work, do all in the name of the Lord Jesus Christ, giving thanks to God the Father through Him".

Also, this:

Catholics, in their ecumenical work, must assuredly be concerned for their separated brethren, praying for them, keeping them informed about the Church, making the first approaches toward them. But their primary duty is to make a careful and honest appraisal of whatever needs to be done or renewed in the Catholic household itself, in order that its life may bear witness more clearly and faithfully to the teachings and institutions which have come to it from Christ through the Apostles.

For although the Catholic Church has been endowed with all divinely revealed truth and with all means of grace, yet its members fail to live by them with all the fervor that they should, so that the radiance of the Church's image is less clear in the eyes of our separated brethren and of the world at large, and the growth of God's kingdom is delayed. All Catholics must therefore aim at Christian perfection(24) and, each according to his station, play his part that the Church may daily be more purified and renewed. For the Church must bear in her own body the humility and dying of Jesus,(25) against the day when Christ will present her to Himself in all her glory without spot or wrinkle.(26)

All in the Church must preserve unity in essentials. But let all, according to the gifts they have received enjoy a proper freedom, in their various forms of spiritual life and discipline, in their different liturgical rites, and even in their theological elaborations of revealed truth.

In all things let charity prevail. If they are true to this course of action, they will be giving ever better expression to the authentic catholicity and apostolicity of the Church.

Recommendations for Practicing Ecumenism:
(paraphrased from the Decree on Ecumenism)

• Reform oneself, "Create in me a clean heart, O Lord, and renew a right spirit within me."
• Pray for the unity of the "one, holy, catholic and apostolic church."
• Learn about the "outlook" of our separated brethren and be able to talk about Catholic truth from that starting point.
• Note points of agreement -- this is quite important because the "separated brethren" have many important points in common with Catholics.
  
• It is essential that the doctrine should be clearly presented in its entirety. "At the same time, the Catholic faith must be explained more profoundly and precisely, in such a way and in such terms as our separated brethren can also really understand."
• Talk about doctrine in a way that has been worked out carefully -- avoid polemics.
• "The way and method in which the Catholic faith is expressed should never become an obstacle to dialogue with our brethren."

Moreover, in ecumenical dialogue, Catholic theologians standing fast by the teaching of the Church and investigating the divine mysteries with the separated brethren must proceed with love for the truth, with charity, and with humility. When comparing doctrines with one another, they should remember that in Catholic doctrine there exists a "hierarchy" of truths, since they vary in their relation to the fundamental Christian faith.

As St Ignatius says, don't start trouble where there wasn't any already -- practice the charitable assumption:

..Let it be presupposed that every good Christian is to be more ready to save his neighbor’s proposition than to condemn it. If he cannot save it, let him inquire how he means it; and if he means it badly, let him correct him with charity. If that is not enough, let him seek all the suitable means to bring him to mean it well, and save himself.

Also, look at the recent CONGREGATION FOR THE DOCTRINE OF THE FAITH.

Different dimensions of the work of ecumenism can be distinguished: above all, there is listening, as a fundamental condition for any dialogue, then, theological discussion, in which, by seeking to understand the beliefs, traditions and convictions of others, agreement can be found, at times hidden under disagreement. Inseparably united with this is another essential dimension of the ecumenical commitment: witness and proclamation of elements which are not particular traditions or theological subtleties, but which belong rather to the Tradition of the faith itself.

Even more, more than you ever would want to read, but I want to have a place to keep track of it all!

• There's this off the cuff talk by Pope Benedict when he visited the USA.
• Father Hardon on Catholic Ecumenism and Russia
• Satis Cognitum by Pope Leo (1896)
• Mortalium Animos by Pope Pius XI (1928)
• Ut unim sint by John Paul II -- some commentary here.