On theological reasons behind a very common Durga / Caṇḍikā dhyana

Normal Reason: rAghava bhaTTa says so and is ratified by the author of prapancha sAra and IshAna shiva in his paddhati. Spiritual reason: The great and the high warlock, aghora parameshvara holds a trishUla in his hands… and according to the devI saptashatI the same shUla is given to chaNDikA parameshvari… for the D700 verily saysshUlaM shUlAd vinishkR^iShya… As per kShemarAja’s commentary on the weapons being held by aghora parameshvara, he says about the shUla: ..”ichChA GYAna kriyAyogi svAtantrya shakti daNDena trishUlena pAshatraya shAtanaM” “Striking down the three bonds [ego, karma, illusion] with the staff of absolute autonomy (svātantrya-śakti), which is conjoined with the powers of Will, Knowledge, and Action (icchā-jñāna-kriyā).”