For I bear them witness that they have a zeal for God, but not according to accurate knowledge.—Rom. 10:2.
“They did not lack zeal; they lacked knowledge (not “head” knowledge, gnosis, but “real” knowledge, perception, or recognition, epignosis). As a result of their lack of knowledge, their zeal became misguided. Interestingly, zeal (zelos) is most often translated “jealousy” in Paul’s epistles, context making the difference. But in its essence, zeal is jealousy, and it can be in a healthy sense. Paul is saying that because the Jews lacked spiritual perception, their jealousy was for their religious traditions rather than the things of God. And Paul should know, as that is what he was zealous/jealous for (Acts 22:3; 21:20; Gal. 1:13–14; Phil. 3:6).” Kenneth Boa and William Kruidenier