The fourth chapter of the Gita opens with the dramatic statement
Imam Vivasvate Yogam Proktavaan Aham Avyayam
Vivasvaan Manave Praaha Manurikshvaakave Abravit
Of this Guru-Parampara, Lord Krishna and Lord Manu are not with us in bodily form. But Lord Vivasvaan is ever with us - giving us light, heat and knowledge as Surya-Narayana.
It is well known that Rshi Yajnavalkya did penance on Lord Surya and received the Shukla Yajur Veda through the lord's grace. Srimad Bhagavatham gives the stuti of Rshi Yajnavalkya extolling lord Surya.
Some astrological classics state that Lord Surya if suitably placed in Navamsa gives the secret knowledge of Vedanta and Bhagavad Gita.
Lord Surya is pleased even by humble and sincere Namaskar daily.
So - Gita students - if you make it a practice of worshipping lord Surya daily, you will get amazing results - try it for yourself!