Scripture records no other moments for him in Mark — or in any Gospel narrative.
Who they were
✦Scripture gives no words or actions — but his epithet speaks: this was a man of fire and conviction, a former revolutionary (or at least a man known for zeal) who redirected his passion to following Jesus.
✦Consider the company he kept: Simon the Zealot and Matthew the tax collector — a Jewish nationalist and a Roman collaborator — both among the twelve. Jesus's kingdom holds together people the world says cannot mix.