Albert Schweitzer mentions in his book "The Quest of the Historical Jesus":

Not only do the events lack historical connection; we have no indication of a connecting thread in the actions and discourses of Jesus, because the sources give no hint of the character of his self-consciousness. They confine themselves to outward facts. We only begin to understand these historically when we can mentally place them in an intelligible connection and conceive them as the acts of a clearly defined personality.