The Krishna Upanishad belongs to the Atharvaveda. As the name suggests deals with the incarnation of Lord Krishna. It deals with the virtues, qualities, objects, and spiritual practices associated with the incarnation of Lord Krishna and explains the significance of his incarnation. At the beginning of the Upanishad, we are told how the gopis became attached to Lord Krishna. They were sages who were overwhelmed by the beauty of Rama and wanted to embrace him.  Rama told them that they would get their wish fulfilled when they would be born as gopis and enjoy the company of Krishna. The Upanishad also explains how various entities and divinities manifested in the life of Krishna. The Upanishad is  devotional rather than philosophical in nature, which is characteristic of many  Upanishads