The main exponent of the Kumara or Chatuhsana sampradaya (this knowledge was transmitted to the four Kumaras by the Hamsa avatara), who lived in the 13th century and propagated the doctrine called dvaita advaita, "simultaneous oneness and duality".
Nimbarka presents himself as a disciple of Narada Muni and says that for a period of his life he lived in Naimisharanya.
This philosophical school has centers in the area of Mathura-Vrindavana (Nimbarka was born near Govardhana from a family of Telugu brahmanas), Rajasthan and Bengal, and identifies the Supreme Brahman as the divine couple of Radha and Krishna.
The identification between the savisesha (with form) and nirvisesha (without form) aspects of Bhagavan (the Supreme Person) is called svabhavika-bheda-abheda, "natural difference and oneness", as he sees no contradiction. The two categories of jivas as baddhas (materially conditioned) and muktas (liberated) are temporary as a baddha jiva can become a mukta through the path to realization or sadhana, which is bhakti (the path of devotion) that includes both karma (the knowledge of action and reaction and becoming free from karma) and jnana (cultivated knowledge). The first stage is karma (the ritualistic process), the second is jnana (the cultivation of knowledge), the third is dhyana (meditation), the fourth is prapatti (surrender), and the fifth is guru prapatti (complete dedication to the instructions of the guru).
His most famous works are the Vedanta Parijata Saurabha (commentary to the Vedas and Upanishads), Sadachar prakash (a treatise on Karma kanda), a Gita bhasya (commentary on the Bhagavad-gita), Rahasya sodasi (explanation of the Sri Gopala mantra), Krishna stava raja (establishing the supreme position of Krishna), Prapanna kalpa valli (explanation of Mukunda mantra), Prata smarana stotram (a devotional poem), Kamadhenu Dasa sloki ("ten nectarine verses" about the meditation on Radha Krishna).
Sri Nimbarka (or Kumara) sampradaya starts from Sri Hamsa.
Once the mental sons of Brahma, the most exalted sages Sanaka Kumara and his brothers became confused about the subject of brahma tattva. They questioned their father Brahma. The question was very complex and hard to solve. Brahma meditated on Lord Narayana. Suddenly the Lord appeared there in the form of a white swan who was the very personification of knowledge. He solved their doubt and told them about the topmost path of worship. This initiation given by Lord Hamsa was the beginning of the Sanakadik sampradaya. Still today, in the Nimbarka sampradaya, after glorifying Lord Hamsa, the sages known as the four Sanakadiks (or the four Kumaras) are glorified.
Sri Nimbarka is always engaged in different forms in the intimate service of the Lord. In this sampradaya Sri Goloka Bihari Radha Krishna is considered the topmost essence of life.
In this age of kali this topmost ancient sampradaya maintains everywhere dharma and tradition of worship. In many ancient places of the sampradaya, in this age of modernization, the devotional practice (sadhna) and the emotions of the sampradaya meet at the confluence of the Triveni of this modern age.
Those living entities who follow the instructions of the acharyas eventually achieve salvation. Steady attachment for the holy dhama, the holy name and the spiritual master (guru govinda nishtha) is the topmost announcement of our Vedic sanatana Vaishnava dharma. "acharyam devo bhava". "acharya mam vijaniyat". Consider the acharya as your worshipable deity. The acharya is My own form. Therefore through the passage of this tradition, following the instructions of the acharya, we can achieve the eternal shelter of our goal, the lotus feet of Shri Shri Radha Goloka Bihari. May the Lord bestow upon you spiritual energy, devotion and attachment for Himself so that your human life will be successful. This life should be for the Lord and remain for Him. Ultimately -
radhaya sahito devo madhvo vaishavottamaih
archyo bandyashcha dhyeyashcha shrinimbarkapadanugaih
- Shri Nimbarka-Sudha
"For the followers of Shri Nimbarkacharya the only worshipable Shri Radha along with Madhava, Shri Shri Radha Golok Bihari is the only deity which should be worshipped, which should be prayed to and upon which we should meditate. This is the only goal which is universally accepted by all. In the end, offering respectful obeisances to the lotus feet of all the Devacharyas of the guru parampara and known and unknown Vaishnavas we pray at their holy feet."
vanchha kalpatarubhyashcha kripa sindhubhya eva cha
patitanam pavanebhyo vaishnavebhyo namo namah
Main part is an Excerpt from: Swami Shri Gopal Sharan Devacharya Maharaj