Justification is God's cleansing human beings of sin and communicating to them his own righteousness through faith in Christ and through baptism. It is also the sanctification and renewal of the inner man through the voluntary reception of the grace and gifts by which man becomes just.
The understanding of justification – what it is and how it is granted and maintained – was a source of conflict during the Reformation.
In their 1999 joint declaration on justification, the Catholic Church and the LWF said that that a more shared understanding of justification signals "a consensus in the basic truths" and that "the differing explications in particular statements are compatible with it."
Point three of the declaration stresses that in "faith we together hold the conviction that justification is the work of the triune God … the foundation and presupposition of justification is the incarnation, death and resurrection of Christ."
"Justification thus means that Christ himself is our righteousness, in which we share through the Holy Spirit in accord with the will of the Father," they said, confessing together that "by grace alone, in faith in Christ's saving work and not because of any merit on our part, we are accepted by God and receive the Holy Spirit, who renews our hearts while equipping and calling us to good works."
The declaration also expressed the shared conviction that "as sinners our new life is solely due to the forgiving and renewing mercy that God imparts as a gift and we receive in faith, and never can merit in any way."
"Therefore the doctrine of justification, which takes up this message and explicates it, is more than just one part of Christian doctrine," but stands "in an essential relation to all truths of faith. It is an indispensable criterion which constantly serves to orient all the teaching and practice of our churches to Christ."
"When Lutherans emphasize the unique significance of this criterion, they do not deny the interrelation and significance of all truths of faith. When Catholics see themselves as bound by several criteria, they do not deny the special function of the message of justification," the document continued.
Lutherans and Catholics, then, "share the goal of confessing Christ in all things, who alone is to be trusted above all things as the one Mediator through whom God in the Holy Spirit gives himself and pours out his renewing gifts."
Critics of the upcoming joint commemoration have voiced concern that the event will gloss-over significant points of Catholic-Lutheran difference, and that it will be used to as an opportunity to push for intercommunion between the Catholic Church and the ecclesial community.
In his comments to journalists, Cardinal Koch, who will be part of Pope Francis' delegation, recognized that the issue of mixed marriages are a "very big pastoral concern for Catholics and Lutherans" alike, but said we have yet to see what the Pope will say about it.
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However, when asked about the issue directly, Vatican spokesman Greg Burke referred to Pope Francis' Nov. 15, 2015, visit to Rome's Lutheran community.
During the encounter Francis was asked by Anke de Bernardinis, a Lutheran woman married to a Roman Catholic man, how she and her husband can be united in communion.
In his response, the Pope said that the answer is "not easy," but that that going to each other's services is a way to participate in the Lord's Supper together.
He said he would "never dare to give permission" on anything regarding Communion because "it's not my competence," but pointed to the common baptism shared between Catholic and Lutherans, explaining that praying together helps keep this common baptism alive.
Burke said that when it comes to Sweden, the Pope likely won't get much more explicit on the issue than that, but added, "you never know in the moment."
Other concerns about the joint commemoration surround points of division not only between Lutherans and Catholics, but also within the global Lutheran community on various social and ethical issues such as homosexuality and abortion.
However, despite the unresolved issues at stake, Junge stressed that in the history of Catholic-Lutheran dialogue "we have seen many things that we thought would be impossible."