In a room sparsely furnished with a desk and wooden chairs, a man instructed Baraa and two other recruits on the values of Islam and a life of sacrifice. When his turn came, Baraa placed his hand on the Quran, the Muslim holy book, and swore "unwavering loyalty and obedience."
With that oath 10 years ago, Baraa joined the Muslim Brotherhood, an exclusive, secretive and disciplined movement that sees itself on a divine mission to establish Islamic rule.
The story of Baraa, 24, and his extended family shows the strength of the Brotherhood: Its cohesion, careful vetting of members and strict rules have propelled an underground movement into a global network that seized power in the Arab Spring. However, some argue that the same closeness and authoritarian nature has worked against the Brotherhood, which now faces challenges to its power throughout the region.
The Brotherhood was toppled in Egypt in a July military coup, and former president Mohammad Morsi will go on trial in November. The coup is also threatening the 6-year-old rule of its Palestinian branch, Hamas, in neighboring Gaza, because the Egyptian military has closed smuggling tunnels under the Gaza-Egypt border, depriving Hamas of millions of dollars in foreign donations and customs revenue. In several Gulf Arab states, the movement has been targeted in a crackdown, and Tunisia's Brotherhood-dominated government faces a backlash.
"They fail to make the transition from a closed organization into an open and broad-based transparent government," Fawaz A. Gerges, director of the Middle East Center of the London School of Economics, said of the Brotherhood. "They behaved, while in government, exactly as they behave internally."
Over several months, AP reporters had rare access in Gaza to the Rantisis, a prominent Brotherhood family that reflects both the deep loyalty of followers and the worries and divisions brought on by recent dramatic setbacks.
The Rantisi family is the perhaps the closest thing to a political dynasty in Gaza's Brotherhood.
Rantisi patriarch Ali, a wealthy landowner, fled his home village in the 1948 war over Israel's creation for the Khan Younis refugee camp in Gaza.
One son, Abdel Aziz, rose in the ranks of the Brotherhood and spent years in and out of Israeli prisons for Hamas activities. In 2004, three weeks after being named Hamas chief in Gaza, Abdel Aziz was assassinated by Israel in a missile strike.
Three other sons, Mohammed, Salah and Nabhan, by then held various positions in the Brotherhood, which formed the core of their lives.
The Brotherhood selected a wife for Mohammed from the movement — Kifah, a devout woman from a wealthy merchant family. It also gave the orthopedic surgeon $2,000 to set up a clinic. In return, Mohammed, 55, treated patients for free once a week at a mosque, paid 2.5 percent of his salary in monthly dues and once sheltered a Hamas bomb maker at the top of Israel's wanted list in his home.
Now Mohammed's three grown children, including Baraa, have joined the Brotherhood, and the younger three are expected to do so eventually.
The Rantisi family reflects the basic recruitment principles of the Muslim Brotherhood: Family and religion.
The neighborhood mosque is the traditional base, particularly in areas where Brothers cannot operate openly. There they coach football teams, organize day trips and tutor students for free, while scrutinizing potential recruits, said Baraa's uncle Nabhan, 58, a former recruitment chief in Khan Younis. They also recruit at high schools.
Smokers and slackers are disqualified, while the most dedicated mosque regulars are offered Brotherhood "try-outs," said Nabhan, a TV and radio technician.
During observation, applicants are expected to perform the five daily prayers at the mosque, rather than at home, particularly the one at dawn, seen as a test of true commitment. Brothers-in-waiting are assigned religious books for discussion.
In the past, applicants had to answer a few questions at the end of probation. Now they have to pass written and oral exams and score at least 70 out of 100. Nabhan said the failure rate in his area was 10 percent.
Hamas has become more selective, Baraa explained.
"We are in the government, and everyone wants to join," he said from his sixth-floor office at a Hamas polling and research center. "Lots of people come for jobs."
Hamas grew out of the Brotherhood in 1987 and is unique in the movement because of its violent struggle against Israel, but follows the same principles as the other branches.
New members are accepted after probation periods of up to three years. Financially successful Brothers serve as benefactors and the movement arranges scholarships for its most promising members.
The smallest unit of the Brotherhood is a "household" of three to five members who during periods underground — such as before Israel's withdrawal from Gaza in 2005 — are not told of the existence of others. Households report to captains, who in turn report to supervisors in charge of mosques.
Baraa's uncle Salah, 52, a gynecologist and Austrian-trained infertility specialist, is a supervisor in charge of about 500 Brothers in a neighborhood near Khan Younis. He decides how to spend the monthly membership dues. One Brother recently got 300 shekels ($84) toward his university tuition, and another $200 toward wedding expenses.
As in Egypt, the Brothers in Gaza have built up an extensive network of clinics, kindergartens, schools and welfare programs as a base for their political support.
The Brotherhood extends from North America to Bangladesh. Brothers in Qatar, Turkey, Malaysia and other countries offer scholarships to Gaza students such as Salah's son Mohammed, who is studying medicine in Tunisia.
Despite its close-knit nature, the Brotherhood — along with the Rantisi household — is now split over direction, amid the crisis in Egypt and its spillover into Gaza.