When the activities for sense gratification, namely the karma-kāṇḍa chapter, are finished, then the chance for spiritual realization is offered in the form of the Upaniṣads, which are part of different Vedas, as the Bhagavad-gītā is a part of the fifth Veda, namely the Mahābhārata. The Upaniṣads mark the beginning of transcendental life.
Vedanta means the "end of the vedas" i.e. the Upanisads.
