2. For I bear them record--or, "witness," as he well could from his own sad experience.
      that they have a zeal of--"for"
      God, but not according to knowledge--(Compare Ac 22:3; 26:9-11; Ga 1:13, 14). He alludes to this well-meaning of his people, notwithstanding their spiritual blindness, not certainly to excuse their rejection of Christ and rage against His saints, but as some ground of hope regarding them. (See 1Ti 1:13).

JFB.