I’ve noticed a generational divide in the quest for Christian unity. People of different ages often articulate different priorities.

Many veterans of the work for Christian unity focus on what Christians have in common. Younger ecumenists often talk of finding peace in the midst of real differences.

This divide follows a natural pattern of healing and reconciliation. It reflects more than just two sides of the same coin.

When two groups first attempt to open a dialogue and mend a wound of division—a division that in some cases goes back hundreds of years, such as between Protestants and Catholics—it can be very delicate in the beginning. There is also a freshness as the relationship is pregnant with possibilities. It can be easy to be giddy with joy and see only positives.

It may be astonishing to discover that you are not as different as you were previously led to believe. You might even find kindred spirits in that “other” group.

The goal is to just start talking. Hundreds of years of separation between Catholics and Protestants have left a lot of hurt feelings and old triggers, and there is no sense stepping on any proverbial landmines in these first encounters. There is joy in just making the initial contact. You can dispel rumors and misconceptions but otherwise leave differences aside—they don’t seem very important when members of the Body of Christ finally start talking after such a long, weary and costly separation.

When the prodigal son returned, his father embraced him. That moment was not the time to hash out who was to blame or identify which differences may remain. Their commonality as family was more important at that moment. [To be clear, I am not suggesting that the divide between Protestants and Catholics is like “father” and “son,” I’m only using that story to illustrate an appropriate behavior when two separated parties finally reconnect for the first time.]

I’m sure this is what it felt like after Vatican II closed in 1965. Catholics in particular had the approval of their church leaders to interact, pray and engage with Protestants in ways that were previously strictly off-limits. Many Protestants were also committed to this (some have been working on unity for much longer) and the ecumenical movement was in full bloom.

As the relationship matures, however, it eventually becomes necessary to transition to a different phase. Focusing on similarities can run the risk of sweeping problems under the carpet if left unaddressed. This method which initially worked so well can devolve into a strained politeness. Ignoring differences also cloaks the full dignity and expression of each party, as people may feel pressure to downplay important parts of themselves for the sake of the relationship.

Ecumenical leaders have been working for decades trying to find out how to achieve the unity Christ himself prayed for (John 17:21). They do not attempt to water down or ignore our differences (as some critics wrongly claim), but often they hope that the differences may not be as severe as they initially seem—perhaps they can be boiled down to difference in perspective or the use of language but are not at their core church-dividing. Their success in this has been astounding. However, after many documents of understanding, clarifying of ideas and mending of social and psychological wounds, sometimes what is left are still some very real differences. What, then, do we do with those?

Recent comments by Vatican officials from the Pontifical Council for Interreligious Dialogue give witness to the process: “We are challenged then to go beyond the confines of tolerance by showing respect to all individuals and communities for everyone desires and deserves to be valued according to his or her innate dignity.”

Respect for similarities is a great first step. The Vatican is right that the next, necessary step is to continue to respect each other even being full aware of each other’s differences—not just tolerating differences but respecting people in those differences.

I’m reminded of a Billy Joel lyric from the song “This Is The Time”: You’ve given me the best of you, but now I need the rest of you.

If you want a person in your life, you want the whole person, not just the picture-perfect persona who shows up on the first date but the real nitty-gritty—”warts and all” as the saying goes.

At some point, the differences and messy disagreements are necessary to sit with. You don’t always have to fix them or find a way around them—you have to first just let them be. By doing this, we may discern the next step in the relationship.

A relationship requires some things in common, but it is not stable if it depends entirely on having things in common. A mature relationship develops when people who are legitimately different can still come to the table in good faith and mutual respect. True respect means accepting the whole person, including all the attributes that don’t neatly fit with yours. Those differences may eventually be reconciled, but we still have to learn to be in relationship until that happens.

This is not in any way to downplay the importance of identifying things in common. I work regularly with Roman Catholics and Evangelical Christians who are still meeting each other for the first time. Those initial encounters are still happening in rural towns in the U.S. where my organization primarily ministers. Identifying commonalities is still very much the work that needs to be done in these areas. The first step, however, must eventually be followed by next steps. Respecting differences is key to this next phase and, once we live this out, I believe it will help us see the phase that comes after it.

Visit Frank Lesko’s Blog The Traveling Ecumenist