This is the process of spiritual realization; one has to receive instruction from a bona fide spiritual master. Kardama Muni was Devahūti's husband, but because he instructed her on how to achieve spiritual perfection, he naturally became her spiritual master also. There are many instances wherein the husband becomes the spiritual master. Lord Śiva also is the spiritual master of his consort, Pārvatī. A husband should be so enlightened that he should become the spiritual master of his wife in order to enlighten her in the advancement of Kṛṣṇa consciousness. Generally strī, or woman, is less intelligent than man; therefore, if the husband is intelligent enough, the woman gets a great opportunity for spiritual enlightenment.
Here it is clearly said (samyak śraddhāya) that with great faith one should receive knowledge from the spiritual master and with great faith execute the performance of service. Śrīla Viśvanātha Cakravartī Ṭhākura, in his commentary on Bhagavad-gītā, has especially stressed the instruction of the spiritual master. One should accept the instruction of the spiritual master as one's life and soul. Whether one is liberated or not liberated, one should execute the instruction of the spiritual master with great faith. It is also stated that the Lord is situated in everyone's heart. One does not have to seek the Lord outside; He is already there. One simply has to concentrate on one's worship in good faith, as instructed by the bona fide spiritual master, and one's efforts will come out successfully. It is also clear that the Supreme Personality of Godhead does not appear as an ordinary child; He appears as He is. As stated in Bhagavad-gītā, He appears by His own internal potency, ātmā-māyā. And how does He appear? He appears when pleased by the worship of a devotee. A devotee may ask the Lord to appear as her son. The Lord is already sitting within the heart, and if He comes out from the body of a devotee it does not mean that the particular woman becomes His mother in the material sense. He is always there, but in order to please His devotee, He appears as her son.