Is it permissible for a Male Ustaaz (teacher) to teach Quran etc.. to a class of mature or close to mature girls who have there hair covered but the face open (without hijab) ? Is it a sine if a Male teacher teaches the above mentioned girls ? Please provide reply with reference.
Yes, to teach, in such a way that the face is open and there is no curtain in the front would be sinful. The sin of not observing hijab is common whether it’s with learning or teaching. The hijab of the face is incumbent on women. Despite of that fact if someone sits in front of her intentionally or she sits in front of a strange man, even though that man may be religious, then the parties involved are committing sin.
Original Source Link (from Way Back Machine archive)