Romans 10:2

They have a zeal of God - They believe their law to have come immediately from God himself, and are jealous of its glory and excellence; they conscientiously observe its rites and ceremonies, but they do not consider the object and end of those rites; they sin more through ignorance than malice; and this pleads in their excuse. By this fine apology for them, the apostle prepares them for the harsher truths which he was about to deliver.

For I bear them record - To bear record means to be a witness; to give evidence. This, Paul was well qualified to do. He had been a Jew of the strictest order Acts 26:5; Philippians 3:5, and he well knew the extraordinary exertions which they put forth to obey the commands of the Law.

A zeal of God - A zeal for God. Thus, John 2:17," The zeal of thine house hath eaten me up;" an earnest desire for the honor of the sanctuary has wholly absorbed my attention; compare Psalm 69:9; Acts 21:20, "Thou seest, brother, how many thousands of Jews there are which believe, and they are all zealous of the law;" Acts 22:3, "And was zealous toward God as ye all are this day." Zeal for God here means passionate ardor in the things pertaining to God, or in the things of religion. In this they were, doubtless, many of them sincere; but sincerity does not of itself constitute true piety; John 16:2, "The time cometh that whosoever killeth you will think that he doeth God service." This would be an instance of extraordinary zeal, and in this they would be sincere; but persecution to death of apostles cannot be true religion; see also Matthew 23:15; Acts 26:9, "I thought that I ought to do," etc. So many persons suppose that, provided they are sincere and zealous, they must of course be accepted of God. But the zeal which is acceptable is what aims at the glory of God, and which is founded on true benevolence to the universe; and which does not aim primarily to establish a system of self-righteousness, as did the Jew, or to build up our own sect, as many others do. We may remark here, that Paul was not insensible to what the Jews did, and was not unwilling to give them credit for it. A minister of the gospel should not be blind to the amiable qualities of people or to their zeal; and should be willing to speak of it tenderly, even when he is proclaiming the doctrine of depravity, or denouncing the just judgments of God.

Not according to knowledge - Not an enlightened, discerning, and intelligent zeal. Not what was founded on correct views of God and of religious truth. Such zeal is enthusiasm, and often becomes persecuting. Knowledge without zeal becomes cold, abstract, calculating, formal; and may be possessed by devils as well as human beings. It is the union of the two - the action of the man called forth to intense effort by just views of truth and by right feeling - that constitutes true religion. This was the zeal of the Saviour and of the apostles.

10:2 They have a zeal, but not according to knowledge - They had zeal without knowledge; we have knowledge without zeal.