Haladini shakti.

Haladini Shakti" literally means Joy-rendering power. In Hindu scriptures it is used for Shri Radha who , it is believed, is the manifestation of this power by which Lord Krishna is all-joy and gifts joy to His devotees.

Radha is considered as a metaphor for the human spirit  her love and longing for Krishna is theologically viewed as symbolic of the human quest for  union with the divine. She has inspired numerous literary works.

Radha is an important goddess in the Vaishnavite traditions of Hinduism. Her traits, manifestations, descriptions, and roles vary by region. Radha is intrinsic with Krishna. In early Indian literature, mentions of her are elusive. The traditions that venerate her explain this is because she is the secret treasure hidden within the sacred scriptures. During the Bhakti moment era in the sixteenth century, she became more well known as her extraordinary love for Krishna was highlighted.

Radha's first major appearance in the 12th-century Gita Govinda in  Sanskrit by Jayadeva as well as Nimbakaracharya's philosophical works.Thus in the Gita Govinda Krishna speaks to Radha:

O woman with desire, place on this patch of flower-strewn floor your lotus foot,
And let your foot through beauty win,
To me who am the Lord of All, O be attached, now always yours.
O follow me, my little Radha.

— Jayadeva, Gita Govinda

However, the source of Jayadeva's heroine in his poem remains a puzzle of the Sanskrit literature. A possible explanation is Jayadeva's friendship with Nimbarkacharya, the first acharya to establish the worship of Radha-Krishna Nimbarka, in accordance with the Sahitya academy 's Encyclopaedia, more than any other acharyas gave Radha a place as a deity.

Prior to Gita Govinda, Radha was also mentioned in text Gata saptasati which is a collection of 700 verses composed in Prakriti language by King Hala The text was written around 1st-2nd century AD. Gatha Saptasati mentioned Radha explicitly in its verse.

Mukhamarutena tvam krsna gorajo radhikaya apanayan | Etasam ballavinam anyasam api gauravam harasi ||

"O Krishna, by the puff of breath from your mouth, as you blow the dust from Radha's face, you take away the glories of other milkmaids."

Radha also appears in the Puranas namely the Padma purana (as an avatar of Lakshmi), the Devi bhagvata purana (as a form of Mahadevi), the Brahma Vaivarta Purana   (as Radha-Krishna supreme deity), the Matsya purana(as form of Devi), the Linga purana (as form of Lakshmi), the Varaha purana(as consort of Krishna), the Narada purana(as goddess of love), the Skanda purana and the Shiva purana The 15th and 16th century Krishnite bhakti poet-saints Vidyapati, Chandidas, Meera bai, Surdas, Swamy Haridas, as well as Narasi mehta (1350–1450), who preceded all of them, wrote about the romance of Krishna and Radha too. Thus, Chandidas in his Bengali-language Shri Krishna Kirtana, a poem of Bhakti, depicts Radha and Krishna as divine, but in human love. Though not named in the Bhagavatha purana, visvanath chakravarthy (c. 1626–1708) interprets an unnamed favourite gopi in the scripture as Radha. She makes appearances in Venisamhara by Bhata narayana (c. 800 CE), Dhvanyaloka by Anandavardana (c. 820–890 CE) and its commentary Dhvanyalokalocana by Abhinava gupta(c. 950 – 1016 CE), Rajasekhara's (late ninth-early tenth century) Kāvyamīmāṃsā, Dashavatara-charita (1066 CE) by kshemendra and Siddhahemasabdanusana by Hemachandra(c. 1088–1172). In most of these, Radha is depicted as someone who is deeply in love with Krishna and is deeply saddened when Krishna leaves her. But, on contrary, Radha of the Rādhātantram is portrayed as audacious, sassy, confident, omniscient and divine personality who is in full control at all times. In Rādhātantram, Radha is not merely the consort but is treated as the independent goddess. Here, Krishna is portrayed as her disciple and Radha as his guru.

Charlotte Vaudeville theorizes that Radha may have inspired by the pairing of the goddess Ekanamsha (associated with Durga) with Jaganatha (who is identified with Krishna) of Puri in Eastern India. Though Chaitanya mahaprabhu (15th century, the founder of Gaudia vaishnavism) is not known to have worshiped the deity couple of Radha-Krishna, his disciples around the Vrindavana region, affirmed Radha as the hladini shakti ("energy of bliss") of Krishna, associating her with the Primordial Divine Mother. While the poetry of Jayadeva and Vidyapathi from Bengal  treat Radha as Krishna's "mistress", the Gaudiya poetry elevates her to a divine consort. In Western India, Vallabhacharya's Krishna-centric sampradaya Pushtimarg had initially preferred Swaminiji as the consort, who was identified variously with Radha or Krishna's first wife Rukmini. Modern Pushtimarg followers acknowledge Radha as the consort.

According to Jaya Chemburkar, there are at least two significant and different aspects of Radha in the literature associated with her, such as Sri Radhika namasahasram. One aspect is she is a milkmaid (gopi), another as a female deity similar to those found in the Hindu goddess traditions. She also appears in Hindu arts as Ardanari with Krishna, that is an iconography where half of the image is Radha and the other half is Krishna. This is found in sculpture such as those discovered in Maharashtra and in texts such as Shiva puranaand Brahma vaivarta purana In these texts, this Ardha Nari is sometimes referred to as Ardharadhavenudhara murti and it symbolizes the complete union and inseparability of Radha and Krishna.

D.M. Wulff demonstrates through a close study of her Sanskrit and Bengali sources that Radha is both the "consort" and "conqueror" of Krishna and that "metaphysically Radha is understood as co-substantial and co-eternal with Krishna." Indeed, the more popular vernacular traditions prefer to worship the couple and often tilt the balance of power towards Radha.

Graham M. Schweig in his work "The divine feminine theology of Krishna" in context with Radha Krishna stated that, "The divine couple, Radha and Krishna, comprise the essence of godhead. Radha is therefore acknowledged by Chaitanyaite Vaishnavas to be part of very center of their theological doctrine. Sacred images of the forms of Radha Krishna, standing together side by side, are elaborately worshiped in the Indian temples. Through her image, her divine character and her amorous and passionate relations with Krishna, Radha is the constant meditation of practitioners.

According to William archer and David Kinsley, a professor of Religious Studies known for his studies on Hindu goddesses, the Radha-Krishna love story is a metaphor for a divine-human relationship, where Radha is the human devotee or soul who is frustrated with the past, obligations to social expectations, and the ideas she inherited, who then longs for real meaning, the true love, the divine (Krishna). This metaphoric Radha (soul) finds new liberation in learning more about Krishna, bonding in devotion, and with passion.

An image of Radha has inspired numerous literary works. For modern instance, the Shri Radhacharita Mahakavyam—the 1980s epic poem of Dr. Kalikal Prasad shukla that focuses on Radha's devotion to Krishna as the universal lover—"one of the rare, high-quality works in Sanskrit in the twentieth century."

 This is taken from the net.