God is both male and female. They are one, but Krishna expands into two, Himself and Radharani, for the sake of divine loving pastimes. If They remained as one, then there is no relationship, there are no pastimes, and there can be no dynamic exchange of love. (Caitanya-caritamrita, Adi-lila, 4.55-56)
In the Brihad-Gautamiya Tantra, Radharani is described as follows: "The transcendental goddess Srimati Radharani is the direct counterpart of Lord Sri Krishna. She is the central figure for all the goddesses of fortune. She possesses all the attractiveness to attract the all-attractive Personality of Godhead. She is the primeval internal potency of the Lord."
Srimati Radharani is the source of the other goddesses. Just as Lord Krishna is the source of all other manifestations and incarnations of God, Radharani is the source of all expansions of the energies of God - the shaktis, or other goddesses. Thus, Vishnu, Rama, even Shiva are all expansions of the one Supreme Being, Krishna, and similarly Lakshmi, Sita, and even Durga are all expansions of this Supreme Feminine form of God, Radharani.
Radha’s love towards Krishna in the terrestrial or customary meaning is not just the relation between a man and woman. The feeling of this love is divine and phenomenal which gives this love a pious form. The philosophical side of this reduces the distance of the support and supportive, also the difference between the worshipper and worshipful is not there. Krishna is the life of Vraj; Radha is the soul of Krishna. That is why, it is said, “Atma Tu Radhika Tasya” (Radha, you are His soul). One form of Radha is, she is a devotee, worshipper of Krishna and in the second form she is the worshipful, devoted by Krishna. ‘Aradhyate Asau itii Radha.’ Radha – Krishna’s love is the symbol of the feeling of being united. When two souls are united, the difference of the other or the second vanishes
Radharani has many names according to Her qualities and characteristics. Some of the names that Radharani is known by include:
Govinda-anandini--She who gives pleasure to Govinda [Krishna];
Govinda-mohini--She who mystifies Govinda;
Govinda-sarvasa--the all-in-all of Lord Govinda;
Shiromani Sarva-kanta--the crown jewel of all the Lord's consorts; and...
Krishnamayi--the one who sees Krishna both within and without.
The descriptions of the beauty of Radharani are wonderfully poetic and descriptive. Actually, the residents of Vrindavana care more for Radharani than they do for Lord Krishna. They know that Krishna can be influenced through Radharani. They know that Radha can bring one to Krishna. She is also the compassionate nature of the Lord, and thus more easily approached than trying to reach Lord Krishna directly. And when we read these descriptions of Radha, it is no wonder why they are devoted to Her. For example, it is explained that Srimati Radharani has unlimited transcendental qualities, of which twenty-five are principal
1) She is very sweet.
2) She is always freshly youthful.
3) Her eyes are restless.
4) She smiles brightly.
5) She has beautiful, auspicious lines.
6) She makes Krishna happy with Her bodily aroma.
7) She is very expert in singing.
8) Her speech is charming.
9) She is very expert in joking and speaking pleasantly.
10) She is very humble and meek.
11) She is always full of mercy.
12) She is cunning.
13) She is expert in executing Her duties.
14) She is shy.
15) She is always respectful.
16) She is always calm.
17) She is always grave.
18) She is expert in enjoying life.
19) She is situated in the topmost level of ecstatic love.
20) She is the reservoir of loving affairs in Gokula.
21) She is the most famous of submissive devotees.
22) She is very affectionate to elderly people.
23) She is very submissive to the love of Her friends.
24) She is the chief gopi.
25) She always keeps Krishna under Her control.
In short, She possesses unlimited transcendental qualities, just as Lord Krishna does. (Ujjvala-nilamani, Sri-radha-prakarana 11-15)
"Although the effulgence of the moon is brilliant initially at night, in the daytime it fades away. Similarly, although the lotus is beautiful during the daytime, at night it closes. But, O My friend, the face of My most dear Srimati Radharani is always bright and beautiful, both day and night. Therefore, to what can Her face be compared?" (Vidagdha-madhava 5.20)
"When Srimati Radharani smiles, waves of joy overtake Her cheeks, and Her arched eyebrows dance like the bow of Cupid. Her glance is so enchanting that it is like a dancing bumblebee, moving unsteadily due to intoxication. That bee has bitten the whorl of My heart." (Vidagdha-madhava)