He heard Paul speak. Hearing is set down first, that we may know that the faith which Luke will commend by and by was conceived of Paul's doctrine. Therefore, when he heard Paul, he hoped to be healed. But the question is, whether this was promised to him specially; for God doth not command us to hope for everything by and by, [1] when he offereth unto us eternal salvation in the gospel. I answer, that this was a singular and extraordinary motion of the Spirit of God in the cripple, as it was on the other side in Paul, when he knew his faith by beholding him only. It may be that many may receive the gospel, and yet they shall not be cured of those diseases wherewith they are vexed. But forasmuch as God was determined to show a token of his grace in the cripple, he prepared his mind before, and made him capable of this that should come upon him. [2] Wherefore we must not make this a common rule, because the cripple believed that he should be healed, but it was a peculiar preparation to receive the gift of healing. And this kind of faith is likewise particular which giveth place to [3] miracles, which many of God's children do want, who are, notwithstanding, indued with the Spirit of adoption. Whom when Paul beheld steadfastly. We know how doubtful and how deceitful a thing the countenance of man is, therefore there could no sure judgment be given thereby of faith, which hath God alone to be witness thereof; but, as I have already said, the cripple's faith was revealed to Paul by the secret inspiration of the Spirit, as he was to the apostles their only guide and master to work miracles.

Footnotes

1 - "Protinus," forthwith.

2 - "Hujus accessionis," of this accession.

3 - "Locum," room for.

Who stedfastly beholding him - Fixing his eyes intently on him. See the notes on Acts 1:10.
And perceiving - How he perceived this is not said. Perhaps it was indicated by the ardor, humility, and strong desire depicted in his countenance. He had heard Paul, and perhaps the apostle had dwelt particularly on the miracles with which the gospel had been attested. The miracles performed also in Icontium had doubtless also been heard of in Lystra.
Had faith to be healed - Compare Matthew 9:21-22, Matthew 9:28-29; Luke 7:50; Luke 17:19; Luke 18:42.

That he had faith to be healed - How did this faith come to this poor heathen? Why, by hearing the word of God preached: for it is said, the same heard Paul speak. And it appears that he credited the doctrine he heard, and believed that Jesus could, if he would, make him whole. Besides, he must have heard of the miracles which the apostles had wrought, see Acts 14:3; and this would raise his expectation of receiving a cure.

The same heard Paul speak,.... That is, preach the Gospel; he was one of his hearers, and faith came to hint by hearing; the Arabic version adds, "he cried unto him"; that is, to Paul, whom he heard:
who steadfastly beholding him; not the lame man beholding Paul, but Paul beholding the lame man, as the Syriac and Ethiopic versions both express it, as also Beza's ancient copy and others; so Peter looked on the man he cured, Acts 3:4.
And perceiving that he had faith to be healed; as he might by his looks, his gestures, his attention in hearing, and it may be by somewhat that he said, as well as by revelation, or a spirit of discerning, which he had.

who steadfastly beholding him--as he did Elymas the sorcerer when about to work a miracle on him.
and perceiving that he had faith to be healed--Paul may have been led by the sight of this cripple to dwell on the Saviour's miracles of healing, and His present power; and perceiving from the eagerness with which the patient drank in his words, that he was prepared to put his own case into the Redeemer's hands, the Spirit of the glorified Physician came all upon Paul, and "with a loud voice" he bade him "stand upright upon his feet." The effect was instantaneous--he sprang to his feet "and walked."

He had faith to be healed - He felt the power of God in his soul; and thence knew it was sufficient to heal his body also.