Acts 21:20

20 And when they heard it, they glorified the Lord and said unto him, Thou seest, brother, how many thousands of Jews there are who have believed, and they are all zealous of the law;

Acts 21:20 Meaning and Commentary

Acts 21:20

And when they heard it
The narrative of the wonderful spread of the Gospel among the Gentiles, and the numerous conversions of them:

they glorified the Lord;
or "God", as the Alexandrian copy, the Vulgate Latin, and Ethiopic versions read; as Paul ascribed all to God, so they give the glory of it to him, and in this they were both agreed:

and said unto him;
perhaps James in the name of them all, and as their mouth:

thou seest, brother;
for so he was to James, both as a believer, and a minister of the word, and as an apostle:

how many thousands of Jews there are which believe;
there were many thousands converted at Jerusalem upon the first preaching of the Gospel, after Christ's ascension; see ( Acts 2:41 Acts 2:47 ) ( Acts 4:4 Acts 4:14 ) ( 6:7 ) and the number might be much increased since; though it may be, that reference is had not only to the number of the members of the church at Jerusalem, but to all the believing Jews in Judea, who were now come up to Jerusalem, to keep the feast of Pentecost; since it is in the Greek, "how many myriads there are", and one myriad contains ten thousand:

and they are all zealous of the law;
of the law of Moses, of the ceremonial law, as Paul might see by their being at Jerusalem, to keep this feast; for though they believed in Jesus of Nazareth as the true Messiah, yet they had not light enough to see, that he was the sum and substance of all the ceremonies of the law, and that they all ended in him; and therefore were zealous in the observance of them, and could not bear to hear of their abrogation.

Acts 21:20 In-Context

18 And the day following, Paul went in with us to see James, and all the elders were gathered.
19 And when he had saluted them, he declared particularly what things God had wrought among the Gentiles by his ministry.
20 And when they heard it, they glorified the Lord and said unto him, Thou seest, brother, how many thousands of Jews there are who have believed, and they are all zealous of the law;
21 and they are informed of thee that thou teachest all the Jews who are among the Gentiles to forsake Moses, saying that they ought not to circumcise their children, neither to walk after the customs.
22 What is it therefore? The multitude must needs come together, for they will hear that thou art come.
The Jubilee Bible (from the Scriptures of the Reformation), edited by Russell M. Stendal, Copyright © 2000, 2001, 2010