Then when the deputy saw This is that which I said, that the snares were broken wherein Elymas kept him entangled, for he was brought by the miracle unto faith, because the reverence of doctrine is the beginning of faith, and the preparation. Therefore, forasmuch as he saw an evident token of the power of God, he knew that Paul was sent of God, and so he began to reverence his doctrine, whereof he did doubt before. If God do now miraculously strengthen in the minds of many the faith of the gospel, which is shaken with so many and such strong engines; if he bring to pass, after an incredible manner, that the course of faith doth pass through a thousand lets, being content with this his grace, let us not murmur against him, or reason the matter with him, as if our condition were worse, if he do not daily show such miracles as we would desire.

Then the deputybelieved - Was convinced that Elymas was an impostor, and that the doctrine of Paul was true. There seems no reason to doubt that his faith was what is connected with eternal life; and if so, it is an evidence that the gospel was not always confined to the poor, and to those in obscure ranks of life.
At the doctrine of the Lord - The word "doctrine" here seems to denote, not the "teaching" or "instruction," but the wonderful effects which were connected with the doctrine. It was particularly the miracle with which he was astonished; but he might have been also deeply impressed and amazed at the purity and sublimity of the truths which were now expanded to his view. We learn nothing further respecting him in the New Testament.

The deputy - believed - This was a proof that the doctrine was true; and that the power of God, from which nothing could be concealed, and which nothing could resist, was with these preachers.
Being astonished - Εκπλησσομενος, Being struck with astonishment, as Elymas was struck with blindness. Thus the word of God is a two-edged sword: it smites the sinner with judgment or compunction; and the sincere inquirer after truth, with conviction of its own worth and excellence.

Then the deputy, when he saw what was done,.... That Elymas was struck with blindness immediately, and that the hand of God was manifestly in it, and there was no juggle nor magic art in the case; it was a plain fact, which was certain and visible:
he believed; in the Lord Jesus Christ, whom the apostle preached:
being astonished at the doctrine of the Lord: both at what was contained in it: for there are many astonishing things in the doctrine of faith; as the birth of Christ of a virgin; the union of the two natures, divine and human, in his person; salvation through his crucifixion and death, and the resurrection of the dead, with others: and also at the miracles which attended this doctrine, and confirmed it; though the Alexandrian copy reads the words thus, "being astonished, he believed in the doctrine of the Lord"; which affords a very easy and natural sense, as that being filled with admiration at the striking of Elymas with blindness, he was induced to believe the doctrine of Christ, preached by Paul and Barnabas, and so the Ethiopic version renders it, "he wondered, and believed in our Lord": and Beza's ancient copy, and others read, "he wondered and believed in God". This deputy we hear no more of afterwards; there is no reason to believe that he quitted his government of this island; though some pretend to say that he did, and followed the Apostle Paul, and went with him into Spain; and that he was left by him at Narbonne in Languedoc in France, and became bishop of that place; which office he held till his death. And though we read of no more converted at this time in Paphos, yet it is highly probable there were others, and that a foundation of a Gospel church state was laid in this place, even though Heathenism still continued. The temple of Venus remained in this place in the "second" century; and in the "fourth" century Venus was worshipped here; yet in the beginning of the "fourth" century, in the council of Nice, Cyril, bishop of Paphos, was present; and in the "fifth" century, a bishop of this place was at the synod of Chalcedon: and in the "eighth" century, Michael, bishop of Taphos, was in the Nycene synod (w). Jerom (x) makes mention of Hilarion, an eminent servant of Christ, who was for some time at Paphos, in the fourth century, and of the many miraculous cures he wrought here; but of the church here, or of any number of believers in Christ, he takes no notice, only of one Hesychius, a disciple; though it is certain there must be a church at this time, as before observed.
(w) Magdeburg. Hist. Eccles. cent. 2. c. 15. p. 193. cent. 4. c. 2. p. 5. c. 15. p. 865. cent. 5. c. 2. p. 6. cent. 8. c. 2. p. 6. (x) Vita Hilarion. fol. 86. C.

Then the deputy, when he saw what was done, believed, being astonished at the doctrine of the Lord--so marvellously attested; compare Mark 1:27. What fruit, if any, followed this remarkable conversion, or how long after it the missionaries remained at Paphos, we know not.

Being astonished at the doctrine of the Lord - Confirmed by such a miracle.