Bhagavad -Gita Akshara-Brahma Yoga and Raja-vidya-Guhya Yoga.Tamil Speech by S.V.Ramani.
In chapter eight Lord Krishna emphasizes the science of yoga. Revealing that one attains whatever one remembers at the end of one’s life the Lord emphasizes the utmost importance of the very last thought at the moment of death. Also he gives information on the creation of the material worlds as well as establishing a distinction between them and the spiritual world. Here he explains the light and dark paths in regards to leaving this material existence, the destination to which they each lead to and the reward received by each. Thus this chapter is entitled: Attainment of Salvation.
In chapter nine Lord Krishna reveals that the sovereign science and the sovereign secret. He explains how the entire material existence is created, prevaded, maintained and annihilated by His external energy and all beings are coming and going under His supervision. The subjects matters covered subsequently are primarily concerned with devotional service and the Lord Himself declares that these subject matters are most confidential. Thus this chapter is entitled: Confidential Knowledge of the Ultimate Truth.
You can listen to the speeches in Tamil about Chapter Eight and Nine of Bhagavad-Gita.