Then Peter and John laid their hands on them, and they received the Holy Spirit.
17. When they had laid their hands. The laying on of hands followeth prayers, whereby they testify that the grace of the Spirit is not included in the external ceremony, which they crave humbly at the hands of another. And yet when they confess that God is the author, they neglect not the ceremony which was delivered them by God to this use; and because...
God had wonderfully owned Philip in his work as an evangelist at Samaria, but he could do no more than an evangelist; there were some peculiar powers reserved to the apostles, for the keeping up of the dignity of their office, and here we have an account of what was done by two of them there - Peter and John.
Commenting on Acts 8:14-25
And when Simon saw,.... Whence it appears, that the Holy Ghost, or his gifts, which were received by imposition of hands, were something visible and discernible; and so something external, and not internal; otherwise they would have been out of Simon's reach, and would not have fallen under his notice; but he saw, that through laying on of the apostles' hands, the Holy Ghost was...