Jnana and karma
Realised souls are illumined seers who have practised the way of discrimination, viveka, and have overcome ignorance, avidya. So, though in embodied state, they are firm in their knowledge of the true swaroopa of Brahman and realise the same Brahman in their atma. Their experience of Brahman as the only eternal Truth gives them clarity of vision regarding the objective world which to them is constituted of Maya. This Advaita doctrine taught by Adi Sankara is explained in great detail by his direct disciple Sureshvara, in the text Naishkarmya Siddhi.
In a discourse, Sri Mani Dravid Sastrigal drew attention to the convincing arguments put forth in the text to show how jnana and karma cannot coexist. The two can run on parallel lines only since Tatva jnana automatically dispels karma. This is owing to the fact that karma thrives on the avidya of jivatmas. Avidya has the power to hide the truth and make people believe as true what is not true. So karma and jnana can never be in the same footing even as lion and a goat cannot be together. In reality, there is no direct opposition between karma and jnana and the Gita expounds the paths of karma, jnana and bhakti as being inter-related in leading the jivatma towards release from samsara.
But the opposition is between Tatva jnana and Avidya. Avidya makes one conscious of his body mind complex and prompts him to do the ordained karmas in the sastras according to one’s age, birth, etc. But the Absolute Truth shining in the inner self of realised souls leaves no foothold for Avidya which gets chased away even as darkness has no existence in the presence of light. With Avidya gone, all karma gets dissociated as a matter of routine and has no relevance in the life of realised souls.