“And James the son of Zebedee, and John the brother of James; and he surnamed them Boanerges, which is, The sons of thunder:”
King James Version (KJV)
3:16 He surnamed them sons of thunder - Both with respect to the warmth and impetuosity of their spirit, their fervent manner of preaching, and the power of their word.
Mr 3:17 Boanerges. Why this title was bestowed on James and John we are not told. Possibly from their power as preachers.