Supreme Offering

What is the supreme offering?
In Srimad Bhagavatam, Maha Bali is ready to offer anything to the Lord who came in the form of a Vamana. He readily surrendered all his possessions. The Lord refused. Why? He cares not about the possessions. He wants the possessor, and hence accepted Mahabali’s supreme surrender.
Surrendering oneself to the Lord or the Guru the supreme offering.