There are different manifestations of the Lord. He is one, but He has become many. He divides Himself into two different expansions, one called kalā and the other vibhinnāṁśa. Ordinary living entities are called vibhinnāṁśa expansions, and the unlimited expansions of viṣṇu-tattva, such as Vāmana, Govinda, Nārāyaṇa, Pradyumna, Vāsudeva and Ananta, are called svāṁśa-kalā. Svāṁśa refers to a direct expansion, and kalā denotes an expansion from the expansion of the original Lord. Baladeva is an expansion of Kṛṣṇa, and from Baladeva the next expansion is Saṅkarṣaṇa; thus Saṅkarṣaṇa is kalā, but Baladeva is svāṁśa. There is no difference, however, among Them. This is very nicely explained in the Brahma-saṁhitā (5.46): dīpārcir eva hi daśāntaram abhyupetya. With one candle one may light a second candle, with the second a third and then a fourth, and in this way one can light up thousands of candles, and no candle is inferior to another in distributing light. Every candle has the full potential candlepower, but there is still the distinction that one candle is the first, another the second, another the third and another the fourth. Similarly, there is no difference between the immediate expansion of the Lord and His secondary expansion.
(Srimad Bhagavatam--3:21:32--purport).

One should not associate with a coarse fool who is bereft of the knowledge of self-realization and who is no more than a dancing dog in the hands of a woman.
The restriction of association with such foolish persons is especially meant for those who are in the line of advancement in Kṛṣṇa consciousness. Advancement in Kṛṣṇa consciousness involves developing the qualities of truthfulness, cleanliness, mercy, gravity, intelligence in spiritual knowledge, simplicity, material opulence, fame, forgiveness, and control of the mind and the senses. All these qualities are to be manifested with the progress of Kṛṣṇa consciousness, but if one associates with a śūdra, a foolish person who is like adancing dog in the hands of a woman, then he cannot make any progress. Lord Caitanya has advised that any person who is engaged in Kṛṣṇa consciousness and who desires to pass beyond material nescience must not associate himself with women or with persons interested in material enjoyment. For a person seeking advancement in Kṛṣṇa consciousness, such association is more dangerous than suicide.
(Srimad Bhagavatam-3:31:34--translation and purport).

The living entity's position is herein likened to a dog's. By chance a dog may have a very rich owner, and by chance he may become a street dog. As the dog of a rich man, he will live very opulently. Sometimes in Western countries we hear of a master leaving millions of dollars to a dog in his will. Of course, there are many dogs loitering in the street without food. Therefore, to liken the conditional existence of the living entity to that of a dog is very appropriate. An intelligent human being, however, can understand that if he has to live the life of a dog, he had best become Kṛṣṇa's dog. In the material world a dog is sometimes elevated and is sometimes on the street, but in the spiritual world, Kṛṣṇa's dog is perpetually, eternally happy. Śrīla Bhaktivinoda Ṭhākura has therefore sung: vaiṣṇava ṭhākura tomāra kukura baliyā jānaha more. In this way Bhaktivinoda Ṭhākura offers to become a Vaiṣṇava's dog. A dog always keeps himself at his master's door and does not allow any person unfavorable to the master to enter. Similarly, one should engage in the service of a Vaiṣṇava and try to please him in every respect. Unless one does so, he does not make spiritual advancement.
(Srimad Bhagavatam--4:29:30-31--purport).