What a wonderful observation and transformation we see in the lives of James and John, the Sons of Thunder!
Oh how I can relate!
The Website, GotQuestions.org does a great job giving insight behind the nickname! Here is their post on subject.
Why did Jesus refer to James and John as the sons of thunder?
In Mark 3, Jesus calls twelve men to be His apostles. Among them are “James son of Zebedee and his brother John (to them he gave the name Boanerges, which means Sons of Thunder)” (Mark 3:17). This is the only place in Scripture that mentions the designation of the sons of Zebedee as the Sons of Thunder, and there is no stated explanation as to why Jesus named them this.
However, Jesus has a purpose for everything He does, so He must have had a good reason for dubbing James and John as “Sons of Thunder.” “Jesus . . . knew all men. He did not need man’s testimony about man, for he knew what was in a man” (John 2:24-25). In other words, Jesus knew the brothers’ nature when He first met them, and He chose “Boanerges” as a fitting nickname.
In one vivid incident, we see that James and John possessed some truly thunder-like qualities. Jesus and His disciples were traveling through Samaria on their way to Jerusalem when they ran into trouble. Jesus attempted to find accommodations for the night in one place but was met with opposition from the villagers, simply because His destination was Jerusalem—a result of Jew-Samaritan prejudice. “When the disciples James and John saw this, they asked, ‘Lord, do you want us to call fire down from heaven to destroy them?’” (Luke 9:54). Jesus rebuked the brothers, and they all went to another village. James and John’s response to the Samaritans reveals a fervency, impetuosity, and anger that could properly be called “thunderous”—and we can be sure that there were other times when James and John lived up to their nickname.
James and John were two of Jesus’ closest friends, being two of the “inner three” disciples (see Matthew 17:1). As the church age began, James was the first apostle to be killed (Acts 12:2), while John was the last to die, although of old age. John’s epistles, written late in his life, hint that he still possessed a fervency of spirit, especially in his denunciations of apostates and deceivers (1 John 2:22; 2 John 7; 3 John 10).
However, it is a fervency tempered by love. In fact, in 1 John the word “love” and its relatives occur over 40 times. When he first met Jesus, John was one of the “Boanerges.” But after walking with Jesus for a lifetime, the “Son of Thunder” earned a new nickname: the “Apostle of Love.”