Contradiction with Genesis 28:12
While Acts 12:9 involves a physical angelic escort, Genesis 28:12 describes angels traveling in a dream rather than interacting in reality.
Genesis 28:12: And he dreamed, and behold a ladder set up on the earth, and the top of it reached to heaven: and behold the angels of God ascending and descending on it.
Contradiction with Acts 1:9
In Acts 12:9, the individual is uncertain of reality believing it to be a vision, whereas in Acts 1:9, the event is described as a factual occurrence of Jesus ascending.
Acts 1:9: And when he had spoken these things, while they beheld, he was taken up; and a cloud received him out of their sight.
Contradiction with Luke 24:37
Acts 12:9 expresses a lack of fear or astonishment, whereas in Luke 24:37, the disciples are terrified and think they see a spirit.
Luke 24:37: But they were terrified and affrighted, and supposed that they had seen a spirit.
Contradiction with Exodus 3:2
In Acts 12:9, Peter doubts the reality of the angel; in Exodus 3:2, Moses doesn’t doubt the angelic appearance through the burning bush.
Exodus 3:2: And the angel of the LORD appeared unto him in a flame of fire out of the midst of a bush: and he looked, and, behold, the bush burned with fire, and the bush [was] not consumed.
Contradiction with 2 Kings 6:17
Acts 12:9 shows disbelief in an angelic presence, while in 2 Kings 6:17, Elisha's servant is able to see the angels when his eyes are opened.
2 Kings 6:17: And Elisha prayed, and said, LORD, I pray thee, open his eyes, that he may see. And the LORD opened the eyes of the young man; and he saw: and, behold, the mountain [was] full of horses and chariots of fire round about Elisha.
Contradiction with John 20:14
In Acts 12:9, the encounter with the angel is not recognized as reality, whereas in John 20:14, Mary does not immediately recognize the risen Jesus but knows it's a significant encounter.
John 20:14: And when she had thus said, she turned herself back, and saw Jesus standing, and knew not that it was Jesus.
Contradiction with Numbers 22:31
Unlike in Acts 12:9 where the angelic encounter is doubted, in Numbers 22:31, Balaam's eyes are opened to see the angel.
Numbers 22:31: Then the LORD opened the eyes of Balaam, and he saw the angel of the LORD standing in the way, and his sword drawn in his hand: and he bowed down his head, and fell flat on his face. [fell...: or, bowed himself]
Contradiction with Matthew 18:10
Acts 12:9 illustrates an angelic encounter perceived as unreal; Matthew 18:10 speaks to angels clearly and evidently present with believers.
Matthew 18:10: Take heed that ye despise not one of these little ones; for I say unto you, That in heaven their angels do always behold the face of my Father which is in heaven.