It says, in part:
"We are keenly aware of the difficult pastoral situations that you will be confronting at the Synod, especially those concerning divorced Catholics. We also share something of the burden you carry in confronting them. Some of us have experienced the pain of divorce in our own lives; and virtually all of us have friends or close relatives who have been so afflicted. We are therefore grateful that attention is being paid to a problem that causes such grievous harm to husbands and wives, their children, and indeed the culture at large.
We are writing you, however, because of our concerns about certain proposals to change the church’s discipline regarding communion for Catholics who are divorced and civilly remarried. We are frankly surprised by the opinion of some who are proposing a “way of penance” that would tolerate what the Church has never allowed. In our judgment such proposals fail to do justice to the irrevocability of the marriage bond, either by writing off the “first” marriage as if it were somehow “dead,” or, worse, by recognizing its continued existence but then doing violence to it. We do not see how these proposals can do anything other than contradict the Christian doctrine of marriage itself. But we also fail to see how such innovations can be, as they claim, either pastoral or merciful. However well meaning, pastoral responses that do not respect the truth of things can only aggravate the very suffering that they seek to alleviate. We cannot help but think of the abandoned spouses and their children. Thinking of the next generation, how can such changes possibly foster in young people an appreciation of the beauty of the indissolubility of marriage?
Above all, we think that the proposals in question fail to take to heart the real crisis of the family underlying the problem of divorce, contraception, cohabitation and same-sex attraction. That crisis, as Benedict XVI observed, is “a false understanding of the nature of human freedom.” Still worse, as he continued, we now have to confront an outlook that “calls into question the very notion of being − of what being human really means” (“Address of His Holiness Benedict XVI on the Occasion of Christmas Greetings to the Roman Curia,” 2012). Not only are the changes in the Church’s discipline called for by some far from adequate to the challenge before us, they seem to us to capitulate to the problem they purport to address.
As has everyone else, we have witnessed the human wreckage brought about by the culture of divorce. But as converts we have also witnessed Christian complicity in that culture. We have watched our own communities abandon the original radical Christian witness to the truth about man and woman, together with the pastoral accompaniment that might have helped them live it.
And so we turn to you. We look to you to uphold Christ’s teaching on the indissolubility of marriage with the same fidelity, the same joyful and courageous witness the Catholic Church has displayed throughout her entire history. Against the worldly-wise who counsel resignation and concede defeat, let the Church once again remind the world of the beauty of spousal fidelity, when lived in unity with Christ. Who is left who can offer the world something other than an echo of its own cynicism? Who is left who can lead it toward a real experience of love? Now more than ever the world needs the Church’s prophetic witness! As Pope Francis said to the thousands of young people at World Youth Day in Brazil:
Today, there are those who say that marriage is out of fashion….They say that it is not worth making a life-long commitment, making a definitive decision, ‘forever,’ because we do not know what tomorrow will bring. I ask you, instead, to be revolutionaries, I ask you to swim against the time; yes, I am asking you to rebel against this culture that sees everything as temporary and that ultimately believes you are incapable of responsibility, that believes you are incapable of true love. World Youth Day, 2013)
As you gather in Rome for the Synod on the Family, we want to offer you the witness of our conversion, which testifies to the attractiveness of the truth about man and woman as it has been “made clear” by Christ through His Church. It is our hope that our witness will strengthen yours so that the Church may continue to be the answer to what the human heart most deeply desires".
You can read more, plus all the names of the signatories, here