Durga kills mahishaasur

 *Durga*

Durgā's feminine power contains the combined energies of all the gods. Each of her weapons was given to her by the various gods: Rudra's trident, Vishnu's discus, Indra's thunderbolt, Brahma's Kamaṇḍalu, etc. etc.

1.Siva's energy her face was developed,

shiva means the auspicious one 

shiva represents the deep silence .

Perception of the formless transcendental Reality is achieved only in the state of deep silence, in the emptiness of the

mind. (sushupti = Siva).

( its understandable , so not going to elaborate )

2.and by yama's energy grew her hair, 

The word yama means "binder, restrainer." It is Yama

who keeps humankind in check. 

so the hairs of devi represents the karma of humans which 

binds us to this samsara leading multiple births and death.

3.and her arms by vishnu's energy, 

 It is this centripetal tendency that

holds the cosmos together and ensures its

continued existence. It pervades all existence

and is therefore known as "Viṣṇu".

so the devi's hands of sattva guna (centripetal force )

holds the entire universe

4..by the Moon's her twin breasts ; 

moon is identified with the Vedic SOMA. 

Soma = Amṛta the nectar of immortality which alludes to the nourishing,nurturing  influence of the Moon on all life forms.

the breast of the devi produces amruta ,which represents

the nourishment of eternal truth ( bramha gnana) through which the sadhaka wins over his death.( which means no more rebirth)

5.her waist came into being by Indra's energy,

Indra represents the all pervading electric energy

(vidyut śakti), he is the ruler of the storm but also the

cause of fertility.

so the waist of devi represents fertility.

( which as i said earlier , devi temples resets the fertility cycles )

 6.and by Varuna's her legs and thighs, 

Varuna means (the Coverer or Binder), 

The name Varuna is derived from the root vr, meaning "to surround, envelop, cover."

 It refers to all that covers, all that is mysterious, cryptic, hidden

referring to the god's character as the enforcer.

 it also represents the inner reality of things, higher

truth (rta), and order in their transcendent aspects, things beyond logical understanding.

7.by the Earth's energy her hips, 

bhu devi or (earth goddess )represents the tolerance and 

compassion and patience.

devi has enough patience and tolerance towards the wrongdoers 

even if at the end times if person falls to her feet she will forgive him/her/ him+her

8.by Brahma's energy her feet,

Brahmā  represents the possibility of existence resulting from a union of pairs of opposites.

it also represents the waking state of externalized awareness (jagrata) — awareness and interaction with the world around us.

 9.her toes by the Sun's energy

 the Sun rising, setting being hidden by the clouds etc.

 In fact sun neither rises not sets nor is covered by anything.

 All of these perception of the Sun are conditioned

by our time and space bound existence upon

earth.Self-luminosity is that which reveals itself and

throws light on other objects.

10. by Kubera her nose

nose of devi has nose pin which has a gem

Whatever treasures are in the earth, they all belong to Kubera. ..this sutra wants to explain that through his kindness do men obtain precious metals and stones from the entrails of the earth.

11. and three eyes were developed by Agni's energy ; 

agni represents divine illumination. . 

agni has 3 faces , which represets 3 vedic fires

Āhavanīya, Dakṣiṇa and Gārhapatya

agnis. ( which we will see some other day)

12.and her eyebrows were the energy of the two twilights,

it represents the two sandhyakaalas ..before sunrise after sunset 

(these 2 times are extremely important for the sadhakas, and mantra becomes more effective during this time)

 13.and her ears Vayu's energy ;

vayu represents the cosmic life breath, the universal "spirit,” the impeller of life and of the living. It is also the substance and the essence of speech (vāc). 

 and the coming into being of the energies of

the other gods became the auspicious goddess.

directly reading durga saptashati without these details would make people think that markandeya rishi is making objectification of the devi's body....however its not ..

so please go through it slowly and understand it

According to a narrative in the Devi Māhātmya, Durgā appeared as a warrior goddess to fight an Asura (an anti- god) named Mahiṣāsura or ’buffalo-demon’.

He had unleashed a reign of terror on earth, heaven and the nether worlds, and he could not be defeated by any man or god, according to a boon given him by Brahmā.

The gods went to entreat the aid of Lord Viṣṇu. Hearing of Mahiṣāsura’s atrocities, Vishnu, Shiva and all of the gods became very angry and beams of fierce light emerged from their bodies.

The blinding sea of light met at the Ashram of a sage named Kātyāyana and Durgā emerged from this coalesced pool of light. The goddess Durgā took the name Kātyāyanī from the priest and emerged from the sea of light.

She introduced herself in the language of the Rig-Veda, saying she was the form of the supreme Brahman who had created all the gods. Now she had come to fight the demon to save the gods.

Mahiṣāsura or the buffalo-demon represents the gross negative aspect of Tamas which obstructs and thwarts spiritual progress. As the personification of the Tāmasic Ahaṁkāra — he constantly and adroitly changes shape whenever he is confronted by Durgā.

We have the incredible capacity for self-delusion and whenever we are confronted we always manage to work our way out and somehow or other justify our actions both to ourselves and to others.

But finally, once we have exhausted all our excuses and self-delusions we are finally vanquished by our higher nature and experience the bliss of Ātma-bodha — self-realization.