Acts 4:21

So when they had further threatened them
Either repeated the same, as before; or added some more severe ones, to terrify them, if possible; not being able to answer their arguments, or invalidate their reasoning: they let them go;
they did not acquit them as innocent persons, but dismissed them from custody: finding nothing how they might punish them;
not being able, though they sought most diligently for it, to fix anything upon them, which might be a cause, or occasion, or pretence of inflicting any punishment upon them: because of the people:
they would not have stuck at the injustice of it, or have been under any concern about offending God; but they were afraid of the people, of losing their credit among them, and lest they should rise up against them, and on the side of the apostles: for all men glorified God for that which was done;
they saw the hand of God in it, and ascribed it to his mercy, goodness, and power, and gave him the glory of it; and therefore to punish the instruments of so great and good a work, would have been esteemed barbarous and wicked, and would have been highly resented by them; since, on the contrary, they judged them worthy of great honour and respect.