Justin Martyr, Apol. 1, 26, states positively that this Simon came from the Samaritan village of Gitta, or Gitton. There are no firm grounds for distrusting Justin here, especially since he himself was a Samaritan by birth, from Sychem.
It is probable that Samaritan national pride was not the least stimulus in considering their kinsman something extraordinary, "the great power of God."
He was a magician; the word "practiced magic" occurs among all the New Testament books only here.
But he was not a magician in the good sense in which the Persian magi came to worship the newborn Lord (Mt 2:1). He was a sorcerer, an enchanter.
At that time, according to Roman and Greek witnesses, many people appeared in various lands of the Greco-Roman world under the names of magi, Chaldeans, mathematicians, and goetes.
They possessed some knowledge of mysterious powers in nature, which was then still little explained. They presented themselves as extraordinary people.
By healing certain diseases, incantations, divination, prophecy, sorceries, charlatan mystery, and various devices, they so worked upon the ignorant masses that they drew many after themselves and were reputed to be something extraordinary.
For the most part they had no systematic doctrines. Yet the ordinary teaching about higher powers was rather strong among them in one form or another.
They imagined that they stood in special relations with these powers. Or at least they claimed that they did, or that they themselves belonged to such higher powers.
Simon presented himself as someone great, some extraordinary person. The people said of him that he was the power of God, the so-called (καλεμένη) great power.
The writer of Acts distinguishes the magician's own opinion of himself from the people's opinion of him.
The latter is more definite and, of course, was based on one or another of his own sayings about himself.
The expression "the great power of God" recalls the language of what later developed as so-called Gnosticism. It imagined aeons as powers flowing from the fullness, or pleroma, of the Godhead.
The people considered their Simon to be one of these powers, and indeed a great or higher power, appearing in human form.
Perhaps Simon did not express himself about himself so definitely. He preferred a certain mysteriousness in his words about himself.
In this way, on the one hand, he stirred the people's imagination more. On the other, he arrogantly enjoyed the lofty opinion that the people had formed of him, as though it were not his own.
Probably Alexandrian philosophical and Eastern theosophical ideas were already sufficiently widespread at that time. Later they entered as one element into the speculative ravings of the Gnostics (cf. Col 2:8ff.; Col 2:20ff.).
This explains the expression "the great power of God."
However it may have been, by his magic Simon so astonished the Samaritan people that all were amazed at him, which is the highest degree of wonder.
As a result all gave heed to his teaching, as in verse 6, from the least to the greatest, what is called both old and young. So strong was the people's fascination with this man, and it continued for no little time.