The spirit of Bhagavad-gītā is mentioned in the Bhagavad-gītā itself. It is just like this. If we want to take a particular medicine, then we have to follow the particular direction mentioned on the label of the medicine. We cannot take the particular medicine according to our own direction or by the direction of a friend, but we have to take the medicine under the direction given on the label of the bottle and as directed by the physician. Similarly, the Bhagavad-gītā also should be taken or accepted as it is directed by the speaker Himself. The speaker of the Bhagavad-gītā is Lord Śrī Kṛṣṇa. He is mentioned in every page of the Bhagavad-gītā as the Supreme Personality of Godhead, Bhagavān.