Teaching theme is related to Patanjali Yoga Sutras 2,36 - when the sadhaka (student) is firmly established in the practice of truth, his words become so potent that whatever he says comes to realisation.
If we don’t experience the truth wholeheartedly within our inner being then we are in the mind where dualities arise.
For example- if we say “I will never eat chocolate again”, as long as one cell of our body holds back and disagrees with the others, our success is not assured. If the stated intention is totally whole-hearted, not one cell dissembling, then we create they reality we desire. This is not the mind but inner voice of our cells, which has the power to implement our intentions.
Ref Light on the Yoga Sutras of Patanjali by Iyengar