We have previously examined the concept of sādhanā bhakti and bhāva bhakti, and the difference between them. The article below explains the difference between them in less technical terms by expanding on concepts introduced in a lecture by Sri Babaji (Bhakti-rasamrta Sindhu lectures, 2017, Vrindavan).
The mind of ordinary people runs toward material things naturally, without requiring conscious effort. For example, no one needs to tell a teenage boy to practice how to become attracted to a teenage girl and vice-versa! It is just natural that this happens, and it happens in different animal species.
By analogy, the mind of a bhāva bhakta runs toward Kṛṣṇa naturally, without any conscious effort. In this context, the word bhāva means a sustained mental state of love for Kṛṣṇa. This is the very nature of the mind of a bhāva bhakta.
Once a teenager thinks they have fallen in love, their thoughts are focused on the person they love. Their mental state causes external things to appear ‘different’ to their perception – unrelated objects remind them of their loved one. They themselves become different persons such that their perception of the external world changes – albeit temporarily.
By analogy, the minds of bhāva-bhaktas are completely absorbed in Kṛṣṇa. All their activities flow from this internal bhāva. The pages of the Bhagavatam are filled with the activities of such bhāva-bhaktas which are expressions of their love for Kṛṣṇa. Such activities are inside-out, that is, they spring from the unconscious mind, or the very nature of the person.
A key difference from the teenage mind, of course, is that the bhāva of a bhakta is eternal, and there is not a hint of motive for self-enjoyment in it. Besides, the object of love is Bhagavān himself.
Clearly prema, the sādhya of bhakti, is a state of the mind. The prema bhakta lives in the bhāva-jagat – mental world of absorption in Kṛṣṇa. All activities of such a person flow from that bhāva, and thus good qualities of the siddhas manifest in the devotee (यस्यास्ति भक्तिर् भगवति अकिंचना सर्वैः गुणैः तत्र समासते सुराः|)
sādhanā bhakti, on the other hand, is outside-in – from the senses to the mind. Kṛṣṇa instructs Arjuna in the Bhagavad-Gitā to bring his mind to Him (मन्मना भव). The sādhaka’s mind does not run naturally toward Kṛṣṇa. Therefore, by performing the activities of bhakti (कृति साध्या!), the effort is to bring the mind to Him on a regular basis, such that one day, bhāva will be attained. That means it becomes ingrained in the mind, after which point, the activities of bhakti will be natural to the person. This is why sādhanā bhakti is called sādhya bhāvā.