"A victor am I over all, all have I known. Yet unattached am I to all that is conquered and known. Abandoning all, I am freed through the destruction of craving. Having thus directly comprehended all by myself, whom shall I call my teacher?"
*****Comment: The context for this verse from the chapter entitled "The Craving" (Tanhavagga in Pali) is that a wandering ascetic asked the Buddha who his teacher was. The purpose being to find out how the Buddha arrives at freedom from craving and consequently, enlightenment.
The Buddha's reply is in keeping with the overall pretext of letting go of worldly cravings and attachments.
And, it presses the emphasis on learning from inside - no teacher needed in other words.