Acts 12:9

9 and having gone forth, he was following him, and he knew not that it is true that which is done through the messenger, and was thinking he saw a vision,

Acts 12:9 Meaning and Commentary

Acts 12:9

And he went out and followed him
He came out from between the two soldiers, and out of that apartment in the prison, in which he was, and followed the angel where he led him:

and wist not that it was true that was done by the angel;
not that he thought the angel was a mere apparition, and all this that was done was a delusion; but he did not know whether this was matter of fact, or whether it was, not represented to him in a visionary way, as what could be, or would be done:

but thought he saw a vision;
imagined he was in a dream or a trance, and only saw these things in a vision, and that they were not really done, the whole was so amazing and astonishing.

Acts 12:9 In-Context

7 and lo, a messenger of the Lord stood by, and a light shone in the buildings, and having smitten Peter on the side, he raised him up, saying, `Rise in haste,' and his chains fell from off [his] hands.
8 The messenger also said to him, `Gird thyself, and bind on thy sandals;' and he did so; and he saith to him, `Put thy garment round and be following me;'
9 and having gone forth, he was following him, and he knew not that it is true that which is done through the messenger, and was thinking he saw a vision,
10 and having passed through a first ward, and a second, they came unto the iron gate that is leading to the city, which of its own accord did open to them, and having gone forth, they went on through one street, and immediately the messenger departed from him.
11 And Peter having come to himself, said, `Now I have known of a truth that the Lord did sent forth His messenger, and did deliver me out of the hand of Herod, and all the expectation of the people of the Jews;'
Young's Literal Translation is in the public domain.