Among the ingredients necessary for liberation, devotion alone is the most important. Constant attempt to live up to one’s Real nature is designated as Bhakti.
“Bhakti is a constant and consistent effort to raise the ego-centre from its welter of false values to the memory and dignity of Self-hood” – Swami Chinmayananda.
A simple example may help to understand this difference Vedanta and Bhakti. If one wants to buy a car, there are two methods he can adopt. He can earn all the money needed and then buy the car for cash; or he can buy the car before having earned all the money and pay for it in installments over a period of some years. Vedanta is the first method, where one acquires all the knowledge in advance. Bhakti is the second method, where the knowledge is gained in installments while doing the devotional practices.
The purpose of all this is to draw a comparison between Vedanta and Bhakti Yoga. There is only a small technical difference. Sri Shankaracharya has used the term “Bhakti” as an equivalent to what is normally called Vedantic enquiry. Enquiry is viewed as a form of worship. Enquiry requires knowledge first, whereas worship does not. The two approaches only start from different origins, but end at the same point, namely, complete union with the Self, which is the culmination of Bhakti, whether Vedantic (Advaitic) or Dwaitic.