“I carried her because she couldn’t walk.”

Still barefoot but no longer wearily carrying his younger sister on his shoulders, 6-year-old Qamar Subuh has a simple explanation for an act that many say underscores the impact felt by Palestinian children in the middle of The Israeli assault on the Gaza Strip.

Video of Qamar carrying his injured sister to the hospital and back in central Gaza was recently widely shared on social media. An NBC News crew spoke with the sisters and their family on Saturday.

Qamar said she and Sumaya Subuh, 5, were on their way to sell boxes of cookies near Al Bureij refugee camp when Sumaya was hit by a car.

When Sumaya needed treatment and was unable to walk, Qamar threw his younger sister on his shoulders and carried her to the hospital. With no ambulance to take them homeQamar said she picked up her sister and walked barefoot in the sun for more than an hour to get home, before a man offered to give them a ride.

Footage of their odyssey was captured by Palestinian journalist Alaa Hamouda, with Qamar praising his courage in a snapshot of the daily reality faced by many Palestinians in the enclave.

The two girls live with their six other siblings and their mother in Al Bureij, a large camp that shelters approximately 49,000 people.

The family lives in a small makeshift tent supported by wooden planks and surrounded by sandbags and rubble. Inside, the family sits against the wall on old, dusty blankets and cushions, their belongings piled in a corner.

The children sing, clap, dance and play with each other while their mother, Hanan, feeds her 1 month old little brother with a bottle.

Qamar recalls the trip with her sister and explains why she helped her.

“She couldn’t walk on her leg,” she said.

Qamar said the two men were selling cookies to raise money so the family could buy diapers and milk for his brother, as well as new clothes and shoes.

“We want better clothes, bedding, utensils, everything,” she said.

But above all, she says, she wants to see her father again, after her family lost contact with him after fleeing northern Gaza.

“We miss him a lot, more than the moon, we miss him,” she said. “We want to go back to see our aunts, see our father and see all of Gaza and the people return there.”

The Israeli army deadly offensive in the north was called the conflict’s “darkest moment” by UN human rights chief Volker Türk.

Dr. Muhammad Al-Mughair, head of Gaza Civil Defense documentation, told NBC News on Sunday that about 1,000 people have been killed and another 670 missing since Israel launched the new offensive there a few weeks.

The mother of Qamar, 33, said the family was from the northern town of Beit Lahia, where Israeli airstrikes have killed dozens of people in recent weeks. She said they left the north because of hunger and have since been displaced four times.

“My husband is lost in the north,” she says. “When he took us to the checkpoint, we lost contact. When he brought us to the border here, he said goodbye to the children and said, ‘God be with you.'”

Hanan said she lives in fear of Israeli airstrikes that keep her up at night, and that her children often go without meals and some days without food at all.

But she expressed pride in her daughter, “who took her sister, carried her, healed her and brought her back,” she said.

“It’s not in his strength to carry it,” she added. “But it had to be.”