Is it permissible to look at the face of a woman wearing a hijab when speaking with her, or is it obligatory to lower the gaze?

Allah commanded lowering the gaze from forbidden things for both genders. Allah, the Almighty, said: (Tell the believing men to lower their gaze and guard their private parts. That is purer for them. Indeed, Allah is Acquainted with what they do. And tell the believing women to lower their gaze and guard their private parts). It is permissible to look at a non-mahram woman out of necessity (such as for buying and selling, giving testimony, medical treatment, and proposing marriage), and the looking must be limited to the extent of the necessity and not exceed it. As for looking with lust, it is forbidden by consensus. If the looking is merely for conversation without necessity, then it seems that lowering the gaze is commanded. And as for the veiled woman who uncovered her face, it is permissible to look at her face to the extent of the need, provided there is no lust or fear of temptation.