Bhakti means 'devotional service.”
Bhakti yoga, also called spiritual path (Bhakti marga) or spiritual practice according to Veda focused on loving devotion towards a personal god. The tradition has ancient roots. Bhakti is mentioned in the Shvetashvatara Upanishad where it simply means participation, devotion and love for any endeavour. The personal god varies with the devotee. It may include a god or goddess such as Ganesha, Krishna, Radha, Rama, Sita, Vishnu, Lakshmi, Saraswati, Shiva, Parvati, Durga among others.
The word yoga means, "to connect." Though yoga is commonly used for health and fitness, the Vedic texts explain that yoga is meant to connect with God. Bhakti means "devotion," or "devotional service," or "pure love." So Bhakti-yoga means to practice connecting with God, and re-establishing our relationship with Him, through acts of love and service, or devotional service. The Sanskrit word bhakti is derived from the root bhaj, which means "divide, share, partake, participate, to belong to". The word also means "attachment, devotion to, fondness for, homage, faith or love, worship, piety to something as a spiritual, religious principle or means of salvation". The term yoga literally means "union, yoke", and in this context connotes a path or practice for "salvation, liberation". The yoga referred to here is the "joining together, union" of one's Atman (true self) with the concept of Brahman (true Reality).
Bhakti connotes devotion, or love, and love implies service. Service refers to that activity which is intended to please the beloved. Thus "devotional service" is an eloquent definition of Bhakti.
Love is the most fundamental drive of every living entity. We cannot be happy without satisfying this desire to love, and we will not be able to perfectly fulfill this desire without permitting its expansion to the most inclusive extent.
"In the primary stage a child loves his parents, then his brothers and sisters, and as he daily grows up he begins to love his family, society, community, country, nation, or even the whole human society. But the loving propensity remains imperfectly fulfilled until we know who is the supreme beloved."
Love can become all-embracing only when we understand that Krishna (example) is the supreme beloved, the root of all creation. By embracing Him we successfully embrace everyone, just as pouring water on the root of a tree successfully nourishes every leaf and branch.
The Nectar of Devotion teaches us the science of loving every one of the living entities perfectly by the easy method of loving Krishna.
The Srimad-Bhagavat Gita lists nine Bhakti practices:
1. Hearing about Devoted God (Krishna).
2. Chanting, or speaking about, God’s (Krishna's) transcendental name, form, qualities, pastimes, paraphernalia, and so on.
3. Remembering God (Krishna).
4. Serving Krishna in all.
5. Offering Krishna respectful worship in His Deity form.
6. Offering prayers to Krishna.
7. Becoming Krishna’s direct servant.
8. Considering Krishna, one's best friend.
9. Surrendering everything to Krishna by serving Him with body, mind, and words.
Example of sage devotee Mira Bai can teach us that by naming Krishna, Krishna how she formed in herself as Krishna. It explains that Bhakti is that fuel of soul which convert us in that form in which we devote our self 100%.