Krishna states a truth that defines the gap between the divine and the created. I know every being — those who lived in the past, those alive now, and those yet to come. But no one knows Me.
A farmer knows every inch of his field — the texture of the soil, where the water pools, which corner gets the most sun. But the soil cannot know the farmer. The knower comprehends the known, but the known cannot grasp the knower in return. This is the nature of the relationship between the divine and creation.
This carries forward from 7.25 — Maya prevents recognition. And the next shloka, 7.27, will explain the root cause of this blindness: the delusion of duality born from desire and aversion.