When news came to the Armenian Club in Baghdad that a U.S.-hosted basketball camp would be held for the city’s elite high school players, there was no doubt Joseph Najarian would represent the club. He was considered to be one of only two quality players on the high school squad — “the other guys were there to fill spots,” he says — and at 16, he was the youngest member of the club’s premier team.

Like the NBA players he watches obsessively, Joseph moves with a graceful lope. He is not particularly tall, but he is long, with stretched arms and legs and lithe fingers. Even his eyelashes are long. His skill comes from practicing four days a week for four hours on the rubber floor at the club’s gymnasium. To explain Joseph’s obsession with the sport, his father and coach, Daron, says simply: “Basketball is in the blood.” (Like nearly all refugee families from Baghdad, they requested their real names not be used.)

At the camp, for five days in the heat of an Iraqi July, he faced new opponents and a new, very regimented, very American style of drills. Competing against the 50 best teenagers in the city was a joy.

At the end, he received two certificates for his participation. One was signed by the camp directors. The other bore not one but two seals of the American eagle and the words “United States of America” arching over the top, similar to the design on a diploma. It also carried the signature of the U.S. ambassador.

A month later, a text message came to Joseph from an unknown number. In Arabic it said: “We know you are working with the Americans. If you don’t stop, we are going to kill you.”

“I thought they were just kidding with me,” he says. “That it was nothing. That it was a joke.” The reaction from his father told him otherwise. A month later another message arrived. Joseph stopped going to school and, worse, playing ball at the club. Then his father found a threatening letter left at their apartment.

Joseph is 18 now, living in Amman, Jordan, with his family, working at a sandwich shop for a kind-hearted Muslim man willing to pay him and his brother under the table. He does not go to school and he does not play much basketball.

“It’s strange here,” he says. “No friends, no family.”

His mother puts it bluntly. “We lost everything. Our friends, our jobs, our schools, our relatives.”

All the family wants now is to immigrate to the United States, ironically the country the Najarians hold responsible for destroying their country, but a place where Mr. Najarian has family. Like nearly all Christian refugees in Jordan, they never expect to return.

The exodus of Iraqis has slowed since the difficult days of 2004 to 2008. The Office of the United Nations High Commissioner for Refugees (UNHCR) says a total of about 30,000 Iraqis are registered in Jordan. In 2011, 7,000 new arrivals registered with the agency. Last year it was half that.

Ra’ed Bahou, CNEWA’s regional director for Jordan and Iraq, says hard numbers are difficult to come by in the Middle East, and the number of registered and unregistered refugees is likely much higher. UNHCR doesn’t release numbers on religious affiliation, but Mr. Bahou believes about 30,000 Iraqi Christians live in Jordan, mostly in Amman. He expects that number to remain constant — a slow trickle in, a slow trickle out and no real change overall.

While the violence after the U.S. military’s surge did abate, life never became anything close to safe. In October 2010, Muslim extremists attacked Our Lady of Salvation Syriac Catholic Cathedral in Baghdad, and the hours-long event left 58 parishioners, priests and police dead. The slaughter cast a long pall over all the country’s Christians.

Iraqis regularly describe that event as the defining moment for them, when everything suddenly and irrevocably changed.

In a new but poor neighborhood with wide main streets and side roads packed with the haphazard dwellings of a developing slum, the Rev. Mansour Mattosha, pastor of Amman’s Syriac Catholic parish, walks up four flights of stairs to visit a parishioner — his niece.

Even before 2003, Amman hosted many Christian communities. Now, among Catholics alone there are Chaldean, Latin, Melkite Greek and Syriac parishes, as well as Coptic, Greek and Syriac Orthodox, Armenian Apostolic and Protestant parishes. Relations among the parishes are good: The overwhelming attitude among the faithful is: “We’re all Christians, and there’s too few of us to bicker.”

Most of these parishes can be found in one part of central Amman, called Hashami Shamali, where many Iraqi refugees live. Father Mattosha comes here several times a week to visit 20 or so families. His is one of the smallest congregations, and he serves it alone. When he arrived, there were about 200 Iraqi families in the parish, as well as the original 50 Palestinian families who established the parish in 1948. Now, the number of Iraqi families has dwindled to about 80; the rest have left for U.N.-sponsored locations from Germany and Sweden to the United States and Canada to Australia and New Zealand. Extended families who used to live in the same village, often on the same block, have ended up in multiple countries.

Fleeing the violence and instability of Iraq has been a mixed blessing, making the refugees feel more secure but also more isolated. There are only about 150,000 Syriac Catholics worldwide. Before the invasion, nearly a third of Syriac Catholics lived in one village in Iraq, Qaraqosh. This was the heart of the Syriac Catholic Church. It is where Father Mattosha and most of his parishioners call home.

“Many talk about going back,” he says, “but they are tired, they despair. So they never do.”

Over his cassock Father Mattosha wears a black coat and black scarf to protect against the cold. At the top of the stairs, he knocks on the door and his niece, Maysoon Esso, answers, letting him into a reception room meagerly warmed by a propane heater. Her youngest son, Majdi, and her daughter, Rana, greet Father Mattosha with kisses to his finely shaved cheeks. The four chatter in Aramaic, the native language of most Iraqi Christians.

The room is sparse but pleasant. Most of the decorations are religious, featuring a long banner of the Virgin Mary, icons on each wall, photographs of Pope Benedict XVI, a nail hung with two rosaries, and a clock adorned with an icon.

The only nonreligious items are two photographs of a young man on an end table, and a calendar above the couch with the same man’s picture printed on it. His name, it turns out, is Roni Esso, Maysoon’s son. Eighteen months earlier, Roni, 25, drowned during a family picnic. Shortly after that, his mother left Iraq with five of her eight surviving children. Maysoon still wears black in mourning.

Roni’s death did not make the family leave. But it made staying harder.

The real reasons they left, the reasons that secured their refugee status and a $350 monthly stipend from UNHCR, were the repeated threats to the family’s oldest son, Ivan. The 29-year-old worked for the electricity company, and the work took him daily outside of Qaraqosh for jobs in and around the northern city of Mosul. That made him an easy target, and threats were common. One day, he narrowly escaped serious injury from a car bomb. The threats kept coming.

Soon after, the Essos paid a driver $1,000, and Maysoon and the five children, aged 12 to 29, left for Amman with a few belongings.

Two married daughters remain in Iraq, along with a son who does not want to leave. Also left behind was Maysoon’s husband, Kyriakos, who is working to repay the debt incurred in the course of their escape.

The apartment they rent belongs to a kind Jordanian man who took pity on them and keeps the rent low.

Life in Amman is safe but tedious. Iraqis aren’t permitted to work and the UNHCR stipends are near subsistence level. Father Mattosha says most families arrive with $5,000 to $10,000, which needs to last an indefinite time. Though money sometimes comes from family abroad, there is little cash left for entertainment beyond TV and the internet, which gives them a vital connection to friends and family.

Maysoon’s oldest boys find irregular work, but she and her daughter, as with most Iraqi adults, stay home and wait for a call regarding their next move.

The younger children can attend school. Majdi is excelling in her studies. CNEWA’s Ra’ed Bahou says local churches have made a point to open parochial schools to Iraqi students. After the trauma many families experience, though, it is not uncommon for children to be kept at home because of a persistent but abstract fear, say officials at UNICEF, the U.N.’s agency for children.

At summer Bible camps CNEWA supports for Jordanian and Iraqi children, one of the most important activities is art therapy. Mr. Bahou says psychological trauma is poorly understood among refugee families, and helping identify and counsel children with problems has become a priority. Healthcare, in general, receives a lot of attention from CNEWA. Two congregations of Dominican sisters were brought from Iraq to administer the Italian Hospital, a respected medical facility in Amman, and a mother-and-child clinic in Zerqa, a city near Amman.

“When an Iraqi goes to the Italian Hospital or our clinic and he sees that the management is Iraqi, there is something to that,” Mr. Bahou says. “It’s not that it’s more friendly, but they are familiar with each other.”

Many know each other from attending weekly religious services. Maysoon attends a catechism class that gathers 100 women each week. The attraction is as much social as spiritual. Many families attend several churches. The Najarian family goes to services at Chaldean, Coptic and Latin churches because they are nearby, even though the family is Armenian Apostolic.

For adults who cannot work and do not have money to spend, all they have left is church.

On one Tuesday night, around 200 members of the 5,000-strong Chaldean community in Amman arrive outside a five-story apartment building in Jabal Weibdeh, an old hilltop neighborhood known for its elegant homes and galleries.

The parishioners, most of whom travel to the posh district to attend the Divine Liturgy, walk down a long flight of steps from the road to the garden on the bottom floor. Most go straight to a shrine of Our Lady of Iraq, stand on the paver stones, lower their eyes for a moment, then kiss their hand and caress the statue’s brow.

The makeshift church shows how impermanent the presence may be. The glassed-in vestibule holds a shrine to the Virgin Mary, a plaster statue of Jesus with broken and taped-up hands and a two-page brochure from UNHCR. The chapel comprises the reception and living rooms of what was once an apartment. Once the liturgy begins, the seating spills into the vestibule, the former pantry and the bedroom.

After the service, the apartment-turned-church clears quickly and the congregants breathe in the brisk, fresh air in the garden. The high walls obscure the distinct hills of Amman. The small clusters of people speak the Chaldean dialect of Aramaic. For a moment, the scene does not sound or feel Jordanian.

Then it comes time to leave. They walk up the stairs and return to a place that is not their own. None of them wanted to come here. Few will ever go back home.

Cory Eldridge is a writer and photographer based in Jordan.