Adam Clarke on Acts 12:8

Gird thyself - It seems Peter had put off the principal part of his clothes, that he might sleep with more comfort. His resuming all that he had thrown off was a proof that every thing had been done leisurely. There was no evidence of any hurry; nor of any design to elude justice, or even to avoid meeting his accusers in any legal way. It appears that the two soldiers were overwhelmed by a deep sleep, which fell upon them from God.