Great authorities like Bhīṣma have explained that love of Godhead means completely giving up all so-called love for any other person. According to Bhīṣma, love means reposing one's affection completely upon one person, withdrawing all affinities for any other person. This pure love can be transferred to the Supreme Personality of Godhead under two conditions—out of ecstasy and out of the causeless mercy of the Supreme Personality of Godhead Himself.
Love of Godhead means
SB Canto 2
Attainment of love of Godhead means complete freedom from all other attractions. The conditioned soul has many aspirations such as becoming a religious man, a rich man, or a first-class enjoyer or becoming God himself, or becoming powerful like the mystics and acting wonderfully by getting anything or doing anything, but all these aspirations should be rejected by the prospective devotee who actually wants to revive his dormant love of God. The impure devotee aspires after all of the abovementioned material things by perfection of devotion. But a pure devotee has none of the tinges of the above contaminations, which are the influence of material desires, impersonal speculations and attainment of mystic powers. One can attain the stage of love of God by pure devotional service, or by "a learned labor of love," for the sake of the devotee's lovable object, the Personality of Godhead.
Other Books by Srila Prabhupada
Nectar of Devotion
Bhakti means application of love. Bhaja sevayā. When you love you serve somebody. That is called bhakti. Therefore, what kind of love? That is also described here. Ahaitukī—without any motive. Here in this material world, I love you, you love me, with a motive of sense gratification. Actually there is no love in the world, material world. The show of love is there with a motive. Here love of Godhead means ahaitukī—without any motive. Ahaituky apratihatā. Apratihata means without being deterred, without being impeded. If you develop your love of Godhead... You must know first of all what is that God, Adhokṣaja, because beyond your mental perception. But fortunately, if you understand what is God, and when you begin to love Him without any motive... Generally we go to temple, to church, or to mosque, anywhere, the place of worship, "O God give us our daily bread." There is a motive. Similarly, others also, they go to the temple, "O God, I am in need of money, I am distressed, kindly mitigate my distress, give me some money." There is motive. But here it is said ahaitukī, without any motive. If you can love God who is beyond your sense perception and without any motive, that activities of love will never be stopped. Ahaituky apratihatā—without being impeded. Without being impeded by any material condition. That means that if you actually love God, there is no condition. Because you are poor man you cannot love God, that is not the fact. Or because you are rich man you cannot love God, no, that is also not fact. Because you are not educated you cannot love God, that is also not acceptable. Because you are very much educated, highly philosophical... So many conditions you can bring but all these conditions are not applicable in the business, in the transaction, of loving God without motive. So this is the description of love of Godhead and if we practically try to cultivate this knowledge of Godhead, that is called, that process is called bhakti. That process is called bhakti.