They glorified the Lord - They gave praise to the Lord for what he had done. They saw new proofs of his goodness and mercy, and they rendered him thanks for all that had been accomplished. There was no jealousy that it had been done by the instrumentality of Paul. True piety will rejoice in the spread of the gospel, and in the conversion of sinners, by whatever instrumentality it may be effected.

Thou seest, brother - The language of tenderness in this address, recognizing Paul as a fellow-laborer and fellow-Christian, implies a wish that Paul would do all that could be done to avoid giving offence, and to conciliate the favor of his countrymen.

How many thousands - The number of converts at this time must have been very great. Twenty-five years before this, 3,000 had been converted at one time Acts 2, and afterward the number had swelled to some more thousands, Acts 4:4. The assertion that there were then "many thousands," implies that the work so signally begun on the day of Pentecost in Jerusalem had not ceased, and that many more had been converted to the Christian faith.

Which believe - Who are Christians. They are spoken of as believers, or as having faith in Christ, in contradistinction from those who rejected him, and whose characteristic trait it was that they were unbelievers.

And they are all zealous of the law - They still observe the Law of Moses. The reference here is to the law respecting circumcision, sacrifices, distinctions of meats and days, festivals, etc. It may seem remarkable that they should still continue to observe those rites, since it was the manifest design of Christianity to abolish them. But we are to remember:

(1) That those rites had been appointed by God, and that they were trained to their observance.

(2) that the apostles conformed to them while they remained at Jerusalem, and did not deem it best to set themselves violently against them, Acts 3:1; Luke 24:53.

(3) that the question about their observance had never been agitated at Jerusalem. It was only among the Gentile converts that the question had risen, and there it must arise, for if they were to be observed, they must have been imposed upon them by authority.

(4) the decision of the council Acts 15 related only to the Gentile converts. It did not touch the question whether those rites were to be observed by the Jewish converts.

(5) it was to be presumed that as the Christian religion became better understood - that as its large, free, and catholic nature became more and more developed, the special institutions of Moses would be laid aside of course, without agitation and without tumult. Had the question been agitated at Jerusalem, it would have excited tenfold opposition to Christianity, and would have rent the Christian church into factions, and greatly retarded the advance of the Christian doctrine. We are to remember also:

(6) That, in the arrangement of Divine Providence, the time was drawing near which was to destroy the temple, the city, and the nation, which was to put an end to sacrifices, and effectually to close forever the observance of the Mosaic rites. As this destruction was so near, and as it would be so effectual an argument against the observance of the Mosaic rites, the Great Head of the church did not suffer the question of their obligation to be needlessly agitated among the disciples at Jerusalem.

How many thousands - Ποσαι μυριαδες; How many myriads, how many times 10,000. This intimates that there had been a most extraordinary and rapid work even among the Jews; but what is here spoken is not to be confined to the Jews of Jerusalem, but to all that had come from different parts of the land to be present at this pentecost.

They are all zealous of the law - The Jewish economy was not yet destroyed; nor had God as yet signified that the whole of its observances were done away. He continued to tolerate that dispensation, which was to be in a certain measure in force till the destruction of Jerusalem; and from that period it was impossible for them to observe their own ritual. Thus God abolished the Mosaic dispensation, by rendering, in the course of his providence, the observance of it impossible.

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 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.

{4} And when they heard it, they glorified the Lord, and said unto him, Thou seest, brother, how many thousands of Jews there are which believe; and they are all zealous of the law:

(4) In things indifferent (of which sort the traditions of the Pharisees were not, but rather the ceremonies of the Law, until the time when Christian liberty was more fully revealed to the Jews) charity exhorts us to conform or apply ourselves willingly so far as we may, to our brethren who do not stubbornly and maliciously resist the truth (but are not thoroughly instructed), especially if the question pertains to a whole multitude.

21:20-22 When they heard it. Paul's report of the wonderful success of the gospel. They evidently approved of and sympathized with his work.

Thou seest, brother, now many thousands... believe. The Greek reads: How many tens thousands. There were not only many thousands of Christians in the Jerusalem church, but many thousands of Jewish Christians who had come up to the feast of Pentecost. Twenty-seven years before there were five thousand men who believed in Jerusalem (Ac 4:4).

They are all zealous for the law. Zealots for the law in the Greek. They believed upon Christ as the Messiah, but did not understand that the Old Covenant had passed away to give place to the New (Heb 8:13). Hence, while they observed the Christian rites, they still kept up the forms of Judaism. It took a direct interposition of the Spirit to teach that Gentiles were entitled to baptism without circumcision (Ac 10:46-48). It required a council in Jerusalem to settle the question that Gentile Christians were not to keep the Jewish law (Ac 15:19-21). God taught the church, lesson by lesson, but up to this time that at Jerusalem had not yet learned that they were freed from the obligation to keep the law of Moses.

21:20 They are all zealous for the law - For the whole Mosaic dispensation. How astonishing is this! Did none of the apostles, beside St. Paul, know that this dispensation was now abolished? And if they did both know and testify this, how came their hearers not to believe them?

20-25. they glorified the Lord, &c.-constrained to justify his course, notwithstanding the Jewish complexion of the Christianity of Jerusalem.

21:19-26 Paul ascribed all his success to God, and to God they gave the praise. God had honoured him more than any of the apostles, yet they did not envy him; but on the contrary, glorified the Lord. They could not do more to encourage Paul to go on cheerfully in his work. James and the elders of the church at Jerusalem, asked Paul to gratify the believing Jews, by some compliance with the ceremonial law. They thought it was prudent in him to conform thus far. It was great weakness to be so fond of the shadows, when the substance was come. The religion Paul preached, tended not to destroy the law, but to fulfil it. He preached Christ, the end of the law for righteousness, and repentance and faith, in which we are to make great use of the law. The weakness and evil of the human heart strongly appear, when we consider how many, even of the disciples of Christ, had not due regard to the most eminent minister that even lived. Not the excellence of his character, nor the success with which God blessed his labours, could gain their esteem and affection, seeing that he did not render the same respect as themselves to mere ceremonial observances. How watchful should we be against prejudices! The apostles were not free from blame in all they did; and it would be hard to defend Paul from the charge of giving way too much in this matter. It is vain to attempt to court the favour of zealots, or bigots to a party. This compliance of Paul did not answer, for the very thing by which he hoped to pacify the Jews, provoked them, and brought him into trouble. But the all-wise God overruled both their advice and Paul's compliance with it, to serve a better purpose than was intended. It was in vain to think of pleasing men who would be pleased with nothing but the rooting out of Christianity. Integrity and uprightness will be more likely to preserve us than insincere compliances. And it should warn us not to press men to doing what is contrary to their own judgment to oblige us.