The Āditya purāṇa, Mārkeṇḍeya Purāṇa and Padma Purāṇa tell about a brāhmaṇa who was suffering from leprosy but had a very chaste and faithful wife. He desired to enjoy the company of a prostitute, and therefore his wife went to her and became her maidservant, just to draw her attention for his service. When the prostitute agreed to associate with him, the wife brought her the leprotic husband. When that leper, the sinful son of a brāhmaṇa, saw the chastity of his wife, he finally abandoned his sinful intentions. While coming home, however, he touched the body of Mārkeṇḍeya Ṛṣi, who thus cursed him to die at sunrise. Because of her chastity, the woman was very powerful. Therefore when she heard about the curse, she vowed to stop the sunrise. Because of her strong determination to serve her husband, the three deities-namely Brahmā, Viṣṇu and Maheśvara-were very happy, and they gave her the benediction that her husband would be cured and brought back to life. This example is given herein to emphasize that a devotee should engage himself exclusively for the satisfaction of Kṛṣṇa, without personal motives. That will make his life successful.
Ref >> Srila Prabhupada Vani.