It was a moment of spiritual awakening and their opportunity to let the negativity and pain of their collective pasts wash away.
The quiet emotional moment capped a unique four-day retreat held last weekend in this natural cathedral known as the Palestinian-Jewish Peacemakers Camp.
As each person walked to the river to take part in the cleansing, they sang in Arabic and Hebrew:
Eeshee hilu k'tir, lama neekun mabad
Henei ma tov uma nayim shevet achim gam yachad
(Translation: How good it is to be together.)
DeGroot, a student at the University of California, Berkeley, studying peace and conflict studies, said the experience was incredible.
He washed 54-year-old Jonathan Silverman's hands.
"It was an opportunity to come together with a person I never met before and found we have the same heart and same mind on the issue," the 25-year-old said. "We were able to pray for peace."
DeGroot said he will go home full of pride.
"Oh, my goodness, I have a newfound love for these other nations," he said beaming. "America, yeah, Israel, yes, and Palestine, yes! We have our drama and we have our problems, but we are brilliant people. Let the minority try to ruin the peace. We are the majority, and I am proud to share this mission with them all."
But the powerful moment at the edge of the river might not have happened if the campers hadn't committed to begin the hard work of learning about each other often the first but difficult steps in the process of reconciliation.
Standing upon a small boulder on Camp Tawonga's meadows, Sima Naanish watched with her dark eyes as Israeli Jews and Palestinians encircled a peace pole bedecked with satin ribbons that fluttered gently in the breeze.
Alone, she smiled and tipped her face up to feel the warmth from the early morning sun's rays.
Naanish, after all, is working toward peace.
For 21/2 years, the 35-year-old Palestinian woman was an inmate in an Israeli prison after her brother was killed during a missile attack fired from Israeli gunships on his wedding day in 2001.
Naanish was arrested and jailed for convincing her husband to join the Kataab Shuhada al-Aqsa, the military wing of the Fatah organization and terrorist group.
She wanted to avenge her brother's death. Her husband was soon on the Israeli Army's wanted list and was a fugitive for two years.
"They tried to assassinate him three different times," said Naanish in Arabic as Mira Almubaied translated. "Every time, he got bullets in different parts of his body. On the fourth attempt, they succeeded. He got 77 bullets."
More than a month after her husband was slain, the Israeli Army broke into her home and took her away while she was breastfeeding her 1-year-old son.
She did not want to describe in detail what happened to her while in prison.
"We were beaten on a regular basis," she said.
She now lives in a refugee camp at Tulkarem in Israel with her children, and she is a member of Combatants for Peace, a group she joined after learning that there are Israelis who refuse to join the army and desire peace just as much as some Palestinians do.
To attend the Peacemakers Camp, Naanish left her children again this time for the greater good.
Her journey took her through eight Israeli checkpoints, then a 15-hour flight to San Francisco International Airport and a four-hour bus ride to a Jewish residential camp near Yosemite National Forest.
Naanish's story was just one of many that brought tears, anger, frustration and stunned silence to the campgoers who hailed from Israel, Palestine, Jordan and the San Francisco Bay Area.
"They refuse and insist not to be enemies," said Len Traubman of San Mateo. "They'll go around the world to do it."
Peacemakers is the only camp in the country that brings youth and adults together, Traubman said.
But there are 13 other diverse camp programs in North America supporting the Middle East peace process outside of politics. And there are many more relationship-building organizations abroad with the same purpose.
"Much of the world's eyes are on Jerusalem," Traubman said. "If the people there could heal, the world will notice. There will likely be a shift of attitudes from confrontation to collaboration."
The camp's dining hall, with its roaring fireplace, was a refuge for the 150 people who would otherwise have been soaked by pouring rain.
In contrast to others in their homeland, most of whom will never meet a Palestinian Israeli or a Jewish Israeli, they were there to understand each other.
"Listening has the power to transform and change a relationship," said Traubman who, along with wife, Libby, leads a monthly Jewish-Palestinian Living Room Dialogue group in San Mateo. "They're here to listen without judgment and expand their knowledge."
It took awhile to get to that point, though. First they had to go through icebreakers such as learning the meaning of each other's names. The next day, they got a course on listening with compassion and intent but it seemed much of the group already knew how to do that.
Participants such as Mohammed Atwa, originally from the Gaza Strip, worried they had traveled to the camp for nothing.
"I did not come here to tell people what my name means," said the 26-year-old, who now lives in Kansas City. "There's more important stuff we need to talk about."
So in an impromptu discussion that lasted into the early morning hours Sunday, more than 30 people convinced the camp's planning committee to allow them to come up with an activity that let them talk about the deeper issues they felt were missing.
"I came here seeking," Atwa said. "We know we have a problem between the Palestinians and the Israelis. We know that in this four-day event, we are not going to solve this problem. But if I'm sitting next to an Israeli serving in the army or who might serve in the future. ... It's important for me to hear the other side and explain myself to the other side."
Rina Kedem is on the camp's planning team. The 26-year-old said young leadership is the key to change, and the people that were invited have a lot of power and potential of creating change in Israeli and Palestinian societies.
"A solution is not what you're going to find here, because it's not that easy," Kedem said. "I see this as a beginning. What really matters is what happens after this. People have a lot of high expectations, even though we clarify the goals. It just demonstrates the despair people are at."
The intense dialogue began on Sunday.
In one circle, 23-year-old Reut Tondovski of Haifa, Israel, opened up the discussion and asked Palestinians what their issues are.
A Palestinian asked if it is part of the Jewish mind-set to protect Israel at all costs.
Twenty-two-year-old Beth Peres of Oak Park, Ill., said that in her Hebrew school she was taught that if there was ever another Holocaust, Israel is going to be there to protect Jews.
"That is what I was taught," she said. "That is what I believe."
"The main problem is occupation," said Ranin Boulos, 23, a Palestinian Christian who lives in London. "Israel created her own enemies, and they are now fighting back. What century are we in? People are still under occupation. It is a state where there's no human rights. It's like they are in a cage."
Citing security reasons in 2002, the Israeli government started building a 25-foot-tall barrier with watchtowers and firing posts mainly inside the West Bank and partly along the 1949 "Green Line" between Israel and Jordan.
The structure, according to the Jerusalem Post, is expected to be three times as long as was the Berlin Wall. It is expected to be completed in 2010.
Atwa said the barrier destroyed many farms and villages on the Palestinian side, and thousands of families were separated. Special permission from the Israeli army is needed to visit a family member, and 99 percent of permits are rejected because of security concerns, he said.
Atwa doesn't have family in the West Bank; his still lives in the Gaza Strip.
After Hamas a Palestinian Sunni Muslim militant organization won the Palestinian parliamentary election, Israel closed the Israeli and Egyptian borders this year.
"Gaza is one big prison," Atwa said. "I can't go home. I can be close to home, but I'll be stuck at the Egyptian-Palestinian border."
He hasn't seen his family since 2002.
"I call my family every single day, because I want to have that feeling that I'm still one of them," Atwa said. "Sometimes I'll call and tell them to keep the phone on and tell them just do whatever they want. I just want to be as if I'm sitting there. That's how much I miss that home."
Libby Traubman, Len's wife, said spending time with the younger generation gives her hope that there will be peace in the Middle East.
"Every day, we hear really bad news, and it's easy to think that things aren't working," she said. "But when you meet all these people we know are very engaged in a very grassroots level, these are the things you don't hear in the news. I guess that is what sustains me."
Elad Vazana, an Israeli Jew who is the director of the Sulhita Youth Project, agreed.
"They are more modern, less religious and less conservative," said the 35-year-old, who lives in Nataf, Israel. "(They have) an option to know more, to talk more and go out into the villages. There's more openness."
Now, the real work for the young Palestinians and Israelis starts once they're home.
"We all need to work on ourselves and to be strong enough to deal with reality," said Boulos, the 23-year-old Palestinian. "What we did here is amazing, but it's not enough. We don't live here. The problem is not here. I don't want to let reality hit you and let what you learned here to go down."
Christine Morente can be reached at firstname.lastname@example.org.