After being baptized, Lydia had gotten Paul and Silas to stay with her awhile (Act 16:1). As they went to prayer a young girl, a slave, met them. She had a "spirit of divination" and brought her masters much gain by her
soothsaying (Acts 16:16). William Edwy Vine writes writes on the "spirit of divination:"
(Eng., "python"), in Greek mythology was the name of the Pythian serpent or dragon, dwelling in Pytho, at the foot of mount Parnassus, guarding the oracle of Delphi, and slain by Apollo. Thence the name was transferred to Apollo himself. Later the word was applied to diviners or soothsayers, regarded as inspired by Apollo. Since demons are the agents inspiring idolatry, 1 Corinthians 10:20, the young woman in Acts 16:16 was possessed by a demon instigating the cult of Apollo, and thus had "a spirit of divination."
There is no indication that Paul or Luke believed this notion, of course. Luke simply recorded the belief of the people of Phillipi and much of the world in that time period.
This girl began to follow Paul and his party crying, "These men are the servants of the most high God, which shew unto us the way of salvation" ( Acts 16:16). After many days of this, Paul was troubled, probably for the reasons given by Robert Jamieson, Andrew Robert Fausset and David Brown (Jamieson-Fausset-Brown):