Note 204 — LECTURE IX
Reading edition
The doubt as to these passages (see Note Z) does not arise from the mere appearance of this figure. The idea of Hecate's connection with witches appears also at ii. i. 52, and she is mentioned again at iii. ii. 41 (cf. Mid. Night's Dream, v. i. 391, for her connection with fairies). It is part of the common traditional notion of the heathen gods being now devils. Scot refers to it several times. See the notes in the Clarendon Press edition on iii. v. 1, or those in Furness's Variorum.
Of course in the popular notion the witch's spirits are devils or servants of Satan. If Shakespeare openly introduces this idea only in such phrases as 'the instruments of darkness' and 'what! can the devil speak true?' the reason is probably his unwillingness to give too much prominence to distinctively religious ideas.