This is because bhakti arises from sraddha, which is the characteristic function of the heart that strives toward bhakti alone, which is totally devoid of karma and jnana, and which desires nothing other than the exclusive pleasure of Sri Krsna. Here we can see that bhakti, arising from sraddha, has nothing to do with one's karma. Sraddha is the natural tendency of the heart, which becomes uncovered for the conditioned souls, as one's material attachments dissipate. This begins to happen when, by chance, one comes into contact with suddha bhaktas.