acts 8:15 Who, when they were come down, prayed for them, that they might receive the Holy Ghost: - Free Bible Online

      15, 16. prayed . . . they might receive the Holy Ghost. (For only they were baptized in the name of the Lord Jesus)--As the baptism of adults presupposed "the renewing of the Holy Ghost" (Tit 3:5-7; 1Co 12:13), of which the profession of faith had to be taken for evidence, this communication of the Holy Ghost by the laying on of the apostles' hands was clearly a superadded thing; and as it was only occasional, so it was invariably attended with miraculous manifestations (see Ac 10:44, where it followed Peter's preaching; and Ac 19:1-7, where, as here, it followed the laying on of hands). In the present case an important object was served by it--"the sudden appearance of a body of baptized disciples in Samaria, by the agency of one who was not an apostle, requiring the presence and power of apostles to perform their special part as the divinely appointed founders of the Church" [ALFORD]. Beautiful, too, was the spectacle exhibited of Jew and Samaritan, one in Christ.

JFB.