Viraha is the Feeling of extreme separation. This is an internal mood in which the Bhakta is eternally established until he unites with Bhagawan in the spiritual domain. Viraha bhava at times synonymously used with Gopi-Bhaav but, it might not necessarily be so. The basis of Viraha can also be with respect to Dasya, Sakhya and Vatsalya Bhavas.
Maya and Bhagawan, are eternal, existing irrespective of the creation, maintenance or annihilation of the universe. Maya is not unreal because she is the potency of Bhagawan. The Lord is her master and she is the embodiment of His energy. Energy is always subservient to the energetic, just like a powerful person may not display his power although he does possess it.
Though essentially living entities are spiritual, they are subjected to the Mayic force of Bhagawan, due to their enjoying tendency overpowering their spiritual characteristic.
Achintya bheda abheda is an amalgamation of pure philosophies propagates by the various schools of thought of Dvaita and Advaita. This are the original teachings of Sriman Chaintanya Mahaprabhu.
Shandilya Bhakti sutras explains the characteristics of True Bhakti and how Bhakti can be directed as a means to attract Bhagawan. Bhakti is the nature of the soul, but many times, people do not understand the true meaning of bhakti.
Many scholars and learned men, on the path of spirituality praise the paths of Karma Yoga and Jnana Yoga. These paths are even recommended in the Gita, spoken by the Supreme Lord. But in the same Scripture the Lord establishes the purity and superiority of the simple path of Bhakti which is not as elaborate as the paths of Jnana and Karma. The greatness of Bhakti is its simplicity and its power to enslave the Lord. The Lord says that he is happy to be sold out to the living entity who has surrendered to the feet of the Supreme Being. Bhakti starts with the cultivation of surrendered faith.
Bhakti is the crest jewel of all endeavors both material and spiritual. One who strives for Bhakti alone can be considered most intelligent. All aspects of spiritual discipline are to be considered supportive or supplementary to Bhakti. Bhakti is the life-giver to spiritual pursuits. If spiritual discipline including Karma, Jnana and Yoga is the tree, then Bhakti is the fruit of that tree. Unless spiritual discipline culminates into Bhakti, all spiritual endeavors remain open ended and incomplete.
It is to be understood that the Shandilya Bhakti Sutra is meant for people who want to solely pursue the path of Bhakti to the exclusion of all other paths. Dry Jnana and Vairagya have no place if Bhakti is not the primary driver within spiritual practice. The work exhorts the necessity for Jnana and Vairagya to be solely subservient to Bhakti. Only when these three aspects are well-intentioned, keeping Bhakti as the goal as well as the means, can sadhana of any sort bear fruit.
Bhakti is universal and the highest of all mellows. Jnana can only be considered as a variation within Bhakti, as a by product of deep Bhakti. Jnana devoid of Bhakti can never bring total fulfilment. Bhakti revolves around appreciation of the Supreme Personality of Godhead to the exclusion of everything else. Even in the entire creation, the thing of beauty is in the Creator alone. This is the central theme of Bhakti.
It is to be understood, that among the Shastra, there are three types the Satvika, Rajasik and Tamasik Shastra. The Satvik Shastra is considered topmost and dedicates itself to the most subtle refinement of elevated God-consciousness. It is the ultimate proclamation of the Satvik Shastra that Bhakti is the Topmost form of Sadhana. Even a full blown Jnani has to finally adopt Bhakti, if he is to relieve himself from the last morsel of material consciousness.