"We want to celebrate their innocence today," said the Rev. Dean Curry, lead pastor of Life Center Church in Tacoma. "We want to be grateful for the moments we had with these children."
The boys' grandfather Chuck Cox thanked police, social workers, teachers and everyone who cared for Charlie, 7, and Braden, 5, as well as people who had prayed for the boys after they died.
It "helps us to know that there are good people in the world - good people who fight against evil," Cox said.
At the front of the church's sanctuary, the boys were in a single casket topped with a large flower arrangement that included daisies, roses and sunflowers.
"We know that they're with their mother," Cox said, remembering his daughter, Susan Powell, who has been missing for two years and is presumed dead.
The boys' father, Josh Powell, was in the middle of a custody battle with Cox when he torched his rental home in Graham last Sunday.
Josh Powell was a person of interest in his wife's disappearance in Utah two years ago, and prosecutors consider the fire an admission that he killed her.
Cox gained custody of the children more than five months ago after police arrested Josh Powell's father, Steve, on voyeurism and child pornography charges.
The kids were arriving for a supervised visit when Josh Powell blocked a social worker from entering the home. He then attacked the boys with a hatchet and torched the house, authorities said.
About 1,200 people attended Saturday's public funeral at Life Center Church in Tacoma, Wash. Many of them wore purple and blue ribbons in memory of Susan, Charlie and Braden.
At the service, two teachers shared their memories and read letters from other instructors who had interacted with the boys.
Both were remembered as fun-loving boys who loved nature and life.
"(Charlie) loved to work alongside his mother in the garden," said Tammy Oughton, Charlie's kindergarten teacher. "He had an appreciation of nature that I have never seen in someone so young."
She related stories of how Charlie collected rocks, sticks and bugs during recess, then would carefully leave them by the classroom door after recess was over to he could play with them later. "On many occasions, he would try to sneak in a worm or caterpillar into the class," Oughton said. "He was a good sport whenever I caught him and he would make sure the bug was safe and sound before joining the class."
Oughton said Charlie also loved to write and even would create marketing plans for his books. On one story he wrote about how to grow plants, Charlie worked especially hard on the cover.
"He even included a detailed bar code," Oughton said. "He designed a marketing flyer which included a release date for the book and free seeds to the first 100 people who purchased the book."
His younger brother, Braden, preferred cars and trains, teachers remembered, and last Halloween got to dress up as a Transformer. Braden, teachers said, loved to be tickled.
"He loved building whatever he could envision with brightly-colored magnetic blocks, tinker toys and Legos," said Kristie King, an instructor at a YMCA where Braden was enrolled in a pre-kindergarten program.. "And when he was finished, he wanted everyone to see it."
She said Braden had a contagious joyful energy who was physically strong, loved to be tickled, and never tied of running.
"Braden had an enthusiasm for life and took pleasure in everything," King said.
King said Braden "had a heart of gold, always wanting to show affection."
"Braden liked to hold his teacher's hand and not let go," she said.
Three projection screens inside the church showed a photo slideshow of the boys: pictures of them smiling with their mother, laughing with their grandparents and playing outside.
"We are grateful for the opportunity that we've each had to have felt the joy that these two small children have brought into our lives in their short lives," family member Kirk Graves said in the funeral's closing prayer.
People started lining up outside the church more than an hour before the service was set to begin.
Tony Deponte, 39, said he was in "total shock" when he heard of the boys' deaths.
"The first thing I did was stop and pray for these children," said Deponte, of Tacoma. "The whole community is feeling their loss."
Amanda Morse, of Seattle, was standing outside the church, holding her 5-month-old son, Ronan. She said she wanted the family to know that they weren't alone.
"It was a tragedy that shouldn't have happened," she said.
A private interment will take place Monday at Woodbine Cemetery in Puyallup.