। ॥ ३९९ ॥
In plain words
Once the mind is truly absorbed in the supreme Self, in Brahman beyond every distinction, no difference of any kind is left to be seen. All that remains, at that point, is just talk — words about a duality that was never really there.
Close to the Sanskrit
When the mental mode is [fully] absorbed in the supreme Self, the thought-free Brahman, no distinction whatsoever is seen; then, mere talk alone remains.