2 No one is unaware of the challenge which all this poses to believers. They cannot fail to meet this challenge. Indeed, how could they refuse to do everything possible, with God's help, to break down the walls of division and distrust, to overcome obstacles and prejudices which thwart the proclamation of the Gospel of salvation in the Cross of Jesus, the one Redeemer of man, of every individual? I thank the Lord that he has led us to make progress along the path of unity and communion between Christians, a path difficult but so full of joy. Interconfessional dialogues at the theological level have produced positive and tangible results: this encourages us to move forward. Nevertheless, besides the doctrinal differences needing to be resolved, Christians cannot underestimate the burden of long-standing misgivings inherited from the past, and of mutual misunderstandings and prejudices. Complacency, indifference and insufficient knowledge of one another often make this situation worse. Consequently, the commitment to ecumenism must be based upon the conversion of hearts and upon prayer, which will also lead to the necessary purification of past memories. With the grace of the Holy Spirit, the Lord's disciples, inspired by love, by the power of the truth and by a sincere desire for mutual forgiveness and reconciliation, are called to re-examine together their painful past and the hurt which that past regrettably continues to provoke even today. All together, they are invited by the ever fresh power of the Gospel to acknowledge with sincere and total objectivity the mistakes made and the contingent factors at work at the origins of their deplorable divisions. What is needed is a calm, clear-sighted and truthful vision of things, a vision enlivened by divine mercy and capable of freeing people's minds and of inspiring in everyone a renewed willingness, precisely with a view to proclaiming the Gospel to the men and women of every people and nation.
Source: Ut Unum Sint (Vatican.va)