I see the heavens opened - A figurative expression, denoting that he was permitted to see “into” heaven, or to see what was there, as if the firmament was divided, and the eye was permitted to penetrate the eternal world. Compare Ezekiel 1:1.
Related Commentaries of Acts 7:56
Acts 7:56
56 And said, Behold, I see the heavens opened, and the Son of man standing on the right hand of God.