Nate Saint, Roger Youderian, Ed McCully, and Peter Fleming were also killed. The group, dubbed the “Ecuador Five,” had spent months trying to contact the unreached tribe deep in the jungle.

The Ecuador Five became legend for evangelicals, and inspired thousands of missionaries.

The killing of John Allen Chau at the hands of North Sentinelese tribe he was trying to contact in a similar way to Jim Elliot, has captured the attention of the world this week. His efforts to tell the tribe about Jesus have been called not just foolish but arrogant and villainous, exposing the isolated tribe to disease and going against their wishes to remain apart.

“You guys might think I’m crazy in all this, but I think it’s worth it to declare Jesus to these people,” Chau wrote in a final letter to his family.

“He is no fool who gives what he cannot keep to gain that which he cannot lose.” – Jim Elliot

Chau’s friend John Ramsey called him a “modern day Jim Elliot,” telling CNN that his friend’s death can “make a statement to the world that this faith is worth dying for.”

So, too, did Jim Elliot and the four other men who travelled with him make a statement about Christianity. Elliot’s most famous quote reads, “He is no fool who gives what he cannot keep to gain that which he cannot lose.”

The world this week has been asking, what did Chau give his life for? As Baptist minister and commentator Michael Frost asks, “If a tribe or nation threatens to kill anyone who enters their territory regardless of their intent, is someone a martyr if they are killed in an attempt to spread Christianity to them? I’m thinking not only of John Chau on North Sentinel Island, but missionaries like Jim Elliot of the Ecuador Five. They weren’t killed because of their message, but because they were outsiders. Is this martyrdom?”

Chau, 26, an American missionary and adventurer, had been fascinated by the people on North Sentinel Island, one of the Andaman Islands in the Bay of Bengal. Indian authorities declared travel within three miles (4.8km) of the island, or attempted contact with its inhabitants, a criminal offence, in part to protect the North Sentinelese people, who are vulnerable to diseases brought in from outsiders, but who have also made it clear in various historical interactions that they want to be left alone.

“He was very well prepared for this moment.” – Mary Ho

Chau was a missionary with a small US mission organisation called All Nations International. Mary Ho, who heads up All Nations, told CNN that from his high school days, Chau had developed a “great love for [the North Sentinelese].”

“In the last 10 years he has planned to reach out to them with the love of God.” Ho said all Chau’s decisions, including his studies of sports science and training and working as a wilderness emergency medical technician and classes he took in linguistics and cultural anthropology, were in preparation to share Jesus with the North Sentinelese.

“He was very well prepared for this moment,” Ho said. She believed Chau kept his intention to visit the island a secret because “he didn’t want to endanger other people’s lives.”

In 1956, when Jim Elliot and his group began their mission to the Waodani tribe (then known as the Auca), they too kept their trip a secret.

“We decided that our efforts should be carried forward as secretly as practical so as to avoid inciting other non-missionary groups to competitive efforts that would undoubtedly employ a heavily armed invasion party action overland. This we fear might set back the missionary effort among these Stone Age people for decades,” wrote Nate Saint, the pilot of the mission plane that flew the group to visit the Waodani tribe.

Chau reportedly bribed local fishermen to take him to North Sentinel Island. Two fishermen in 2006 were killed by North Sentinelese tribespeople after their boat drifted too close to the island. In journals shared with The Washington Post by Chau’s mother, he tells of his belief that “God Himself was hiding us from the Coast Guard and many patrols” as they approached the island.

From the fishermen’s boat, Chau used a kayak to approach the island on several occasions before his death. He documented in his diary his first interaction, writing, “Two armed Sentinelese came rushing out yelling … they had two arrows each, unstrung, until they got closer. I hollered, ‘My name is John, I love you and Jesus loves you.’”

He writes that he offered some fish, but when they kept coming towards him, he “turned and paddled like I never have in my life.”

In another encounter, Chau writes that he tried to hand over some fish and a bundle of gifts, but a boy shot an arrow “directly into my Bible which I was holding”.

The Ecuador Five also offered gifts to the Waodani tribe in the 1950s, as a way of establishing friendly contact. They started by dropping gifts from a plane. Using Nate Saint’s missionary plane, they also used an amplifier to speak out friendly Waodani phrases, including “I like you, I like you.” They did this for several months, and even had a gift sent back up to the plane, when a tribe member put it in the bucket in which they had lowered a gift. “It was a parrot in a basket covered by bark cloth,” Nate Saint wrote in his diary. “It was well tied and was complete with a partially nibbled banana inside for the trip! We praise God for this, another indication of His leading and care.”

“It’s weird – actually no, it’s natural. I’m scared.” – John Chau

Soon after the reciprocated gifts, the Ecuador Five moved from dropping gifts by plane to landing the plane on a nearby beach and encouraging face-to-face contact. After a few promising meetings, all five men were killed by spears on the beach.

Chau, too, was killed by a spear. Only the night before his death, he questioned whether his effort to make friendly contact was working, and whether it was worth it.

“It’s weird – actually no, it’s natural. I’m scared,” he wrote. “There, I said it. Also frustrated and uncertain – is it worth me going a foot to meet them? I don’t want to die!”

The Ecuador Five spent months trying to make contact with the Waodani tribe. And the many in the Waodani tribe eventually became Christians, with Jim Elliot’s wife Elisabeth carrying on the work of making friendly contact and telling them about Jesus. Chau spent less than a week making contact with the North Sentinelese before he was killed. But his intentions appear the same.

“This is not a pointless thing – The eternal lives of this [Sentinelese] tribe is at hand and I can’t wait to see them around the throne of God worshipping in their own language as Revelation 7:9-10 states,” Chau wrote in his diary.

In a final message to his family, he wrote “Please do not be angry at them or at God if I get killed. I love you all.”

He signed off: “Soli deo gloria” (glory be to God alone).