O son of Prtha, those who take shelter in Me, though they be of lower birthwomen, vaisyas [merchants], as well as sudras [workers]can approach the supreme destination. It doesnt matter whether a person is born as a sudra, a woman or a vaisya; if he associates with devotees repeatedly or always (sadhu-sangena), he can be elevated to the highest perfection. Narada Muni is explaining this in relation to his own life. The sankirtana movement is important, for regardless of whether one is a sudra, vaisya, mleccha, yavana or whatever, if one associates with a pure devotee, follows his instructions and serves the pure devotee, his life is successful. This is bhakti. Anukulyena krsnanusilanam. Bhakti consists of serving Krsna and His devotees very favorably. Anyabhilasita-sunyam [Bhakti-rasamrta-sindhu 1.1.11]. If one has no desire other than to serve Krsna and His devotee, then his life is successful. This is explained by Narada Muni through this practical example from his own life.