John Calvin Commentary Acts 8:3

"But Saul laid waste the church, entering into every house, and dragging men and women committed them to prison." — Acts 8:3 (ASV)

But Saul. We must note two things here: how great the cruelty of the adversaries was, and how wonderful the goodness of God was, who deigned to make Paul a pastor from such a cruel wolf. For that desire to lay waste the Church with which he was inflamed seemed to cut away all hope. Therefore, his conversion was all the more excellent afterward.

And it is not to be doubted that this punishment was laid upon him by God, after he had conspired with other wicked men to put Stephen to death, thereby becoming the ringleader of cruelty. For God often punishes sins more sharply in the elect than in the reprobate.