What gave the apostles boldness was that they performed miracles. "The very fact that the hearers believed was itself among the signs." "That their hearers believed was the result of the miracles, though the apostles’ boldness itself also contributed somewhat to this."
There is a tradition that here a young pagan woman, Thecla, was converted to Christ. She is called Equal-to-the-Apostles for her labors of good tidings among the Gentiles. She reposed in old age, having received the crown of the protomartyr. Her memory is celebrated on September 24.
Even if fewer than half the city remained among the Christians, nevertheless the apostles undoubtedly laid sufficient seeds of faith here. Later, on this field, great fruits would grow, as is shown even in the acts of one of the newly converted from this place.
The apostles’ boldness in the Lord appeared in this case all the stronger because it was boldness in the Lord, that is, in Christian teaching (see Acts 20:32).
The witness to this was manifested in the fact that He worked signs and wonders by their hands, that is, by the hands of the apostles. They preached as the twelve disciples of Christ did after the Ascension, with the Lord’s cooperation and with the word confirmed by the miracles that followed (see Mk 16:20).
Therefore the apostles did not consider themselves entitled to leave the city. If the Jews could contradict and resist the apostles’ preaching, their malice was powerless against the signs and wonders.
The result was that many of the Gentiles took the apostles’ side. Others remained on the side of the Jews.
From oppression the matter passed to open persecution, which became still more possible for this party when it drew the authorities to its side.
A strong impulse arose first to heap shame and mockery upon the apostles (see Mt 26:6; Lk 18:32), and then to stone them. Learning of this disposition in the hostile party, the apostles withdrew hastily.