Acts 5:19

But the angel of the Lord - This does not denote any “particular” angel, but simply an angel. The “article” is not used in the original. The word “angel” denotes properly a “messenger,” and particularly it is applied to the pure spirits that are sent to this world on errands of mercy. See the notes on Matthew 1:20. The case here was evidently “a miracle.” An angel was employed for this special purpose, and the design might have been:

1. To reprove the Jewish rulers, and to convince them of their guilt in resisting the gospel of God;
2. To convince the apostles more firmly of the protection and approbation of God;
3. To encourage them more and more in their work, and in the faithful discharge of their high duty; and,
4. To give the people a new and impressive proof of the truth of the message which they bore. That they were “imprisoned” would be known to the people. That they were made as secure as possible was also known. When, therefore, the next morning, before they could have been tried or acquitted, they were found again in the temple, delivering the same message still, it was a new and striking proof that they were sent by God.