Dozens of mourners, including the chief rabbi of Israel, attended the emotional service, which was repeatedly interrupted by anguished cries.
"Why seven?" their father, Gabriel Sasson, cried out during a eulogy. "Seven beautiful lilies. So pure. So pure. I did not know there was such a price for children like them."
The bodies of the Sassoon siblings, ages 5 to 16, were flown to Israel overnight from New York and whisked away to Jerusalem in a convoy escorted by police.
The bodies, wrapped in shrouds, were displayed on stretchers for a memorial service in a room crowded with dozens of mourners. After the service, they were buried at Jerusalem's main cemetery.
David Lau, Israel's chief rabbi for Ashkenazi - or European - Jews, described the fire as an unspeakable tragedy and urged the family to remain strong.
"Each one is a flower in God's garden," he said.
The fire has shattered the ultra-Orthodox Jewish community in the Midwood neighborhood of Brooklyn. Investigators believe it was caused when a hot plate left on for the Jewish Sabbath malfunctioned, setting off flames that incinerated the stairs of their home and trapped the children in their second-floor bedrooms as they slept.
The blaze killed four brothers -- David, Yishua, Moshe and Yaakub -- along with three sisters -- Elaine, Rivkah and Sara. Both the mother and a daughter - Gayle Sassoon and 14-year-old Siporah Sassoon - remain in critical condition.
Siporah was awake and alert briefly on Monday, her father said. He said he told her she needs to find the strength to heal. During a remembrance at the Barclays Center on Monday night before the Celtics-Nets game, the names of all of the deceased children were read. Gayle Sassoon remains in a medically induced coma and is unaware of what happened to her family.
The tragedy had some reconsidering the practice of keeping hot plates on for the Sabbath, a common modern method of obeying tradition prohibiting the use of fire on the holy day.
Israeli media have said the family lived in Jerusalem before moving to New York two years ago.
Alon Edri, who identified himself as a rabbi and relative of the family, said it was significant for the religious family to be buried in the Holy Land.
"We believe that being buried in Israel is important because all of your sins are then absolved," he said.
Services were held in Brooklyn Sunday for the siblings, with seven SUVs carrying seven small wooden caskets.
Gabi Sassoon spoke to the crowd of thousands outside the chapel, remembering each and every one of his kids who really had just started living their lives.
"Rivkah, she had so much joy, gave joy to everybody," he said. "Yeshua was so joyful and creative and always tried to make everybody happy."
Many in the close-knit Orthodox Jewish community do not know the family, but their deep faith drew them to the memorial Sunday.
Gabi was at a conference and was not home at the time of the fire, but on Sunday he watched and grieved as he said goodbye to nearly his entire family.
"They all have faces of angels," he said. "I want to ask my children for forgiveness. I did my best and my wife did her best. Please everybody, love your child."
Brooklyn Assemblyman Dov Hikind said the children's remains were placed aboard an El Al flight to Tel Aviv after the services.
"I call this not a tragedy but an absolute disaster," said Hikind, who represents the Brooklyn neighborhood of Midwood where the fire broke out.
Police officers stood guard outside the charred shell of the Sassoon home that once reverberated with the sounds of a thriving, happy family. All of that was silenced in the short but intense fire. A woman named Esther who lived next door said she adored the children.
"Big, beautiful black eyes of the little children," she said. "And kindness, just total kindness."
For those who worshiped at Temple with the Sassoon family, the loss, they say, is immeasurable.
"It's a real tragedy for all of us over here," Vito Vuchris said. "The whole neighborhood is feeling it."
The house had no working smoke detectors on the first or second floors, and firefighters found only one smoke detector in the basement which may have never sounded since the fire spread rapidly to the second floor. By the time the mother awoke, she was unable to get to her children.
"The mother would have had to go into the fire to get to the back bedrooms," FDNY Commissioner Daniel Nigro said. "So I think she valiantly tried, although badly burned, to get out and get help for her children."