Acts 12:9

So Peter followed him out, but he was unaware that what the angel was doing was real. He thought he was only seeing a vision.
BSB · Berean Standard Bible
And he went out, and followed him; and wist not that it was true which was done by the angel; but thought he saw a vision.
KJV · King James Version
And he went out and followed him. He didn’t know that what was being done by the angel was real, but thought he saw a vision.
WEB · World English Bible
And he went out, and followed; and he knew not that it was true which was done by the angel, but thought he saw a vision.
ASV · American Standard Version

Related passages

From the Treasury of Scripture Knowledge, grouped by the word they explain.

he went
Acts 26:19; Genesis 6:22; John 2:5; Hebrews 11:8
wist not
That is, he knew not; wist being the past tense of the obsolete verb to wis, from the Saxon wissan, in German {wissen,} and Dutch {wysen,} to think, imagine, know.
Acts 10:3, 17; Acts 11:5; Genesis 45:26; Psalm 126:1; 2 Corinthians 12:1–3