For I bear them witness that they have a zeal for God, but not according to knowledge.
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Ambrose of Milan
AD 397
I know that you [Emperor Theodosius I] are Godfearing, merciful, gentle and calm, that you have the faith and fear of God in your heart, but often some things escape our notice. Some people have a zeal for God but not according to knowledge. Care must be taken … lest this condition steal upon pious souls.
Having once been one of them himself, Paul understood and bore witness that the Jews fought against the gospel out of zeal for God, yet it was a zeal uninformed by true knowledge. .
According to knowledge The Jews ran with ardour in the paths of the law, but saw not whither they were going; they followed the law, but did not know whither it conducted them. (Calmet)
For "says he, "being ignorant of (the righteousness of) God, and going about to establish their own righteousness, they have not submitted themselves unto the righteousness of God; for Christ is the end of the law for righteousness to every one that believeth."