Why would a sculptor, working with stone and bronze, need a secretary? Rodin was convinced he could not do without one, and in 1902 hired Rainer Maria Rilke. Sculptures were a major source of inspiration to the poet, who had, the year before, married the sculptress Clara Westhoff. In this period Rilke became convinced that his poems should directly relate to objective reality, and should be tangible, like a thing.
This being his ideal, it is perfectly understandable that, when he visited the Louvre in 1907, he was struck by a Greek torso. This was the marble torso, dating from 470 BC and representing Apollo, which had been excavated in 1872 in Miletus. It probably had decorated the local Roman theatre.
Here is, in my own translation, the poem Rilke wrote in 1907 to commemorate his encounter with this impressive shard of Apollo.

Apollo’s archaic torso

We never knew his fabled head
that held the ripening apples of his eyes. And yet
his torso still glows like a candelabrum,
in it his gaze, turned low now,

still holds and gleams. Or else the bow of his breast
would not blind you, and in the silent shifting
of the loins could not hover a smile
towards the middle, where procreation once was born.

Or else this stone would stand deformed and short
beneath the shoulders falling into transparency,
would not be glistening like the wild beast’s fur;

and would not from all its sides
radiate like a star: for there is not a spot here
that does not see you. You must change your life.

Rilke understood that, if one looked intensely at this torso, it was inevitable to also see the elements (the head, the arms, the legs) that had disappeared. Our imagination more or less forces us to fill in the vacant parts. Apollo’s eyes and gaze, though disappeared, are still there if we look at the chest or the abdomen. The whole is included in the fragment. The imagination may supplement the objective, and in doing so itself becomes objective. In the visible image of the imperfect the perfect may be seen, and the incomplete somehow represents the complete.

In front of this Apollo Rilke realized he was looking at his own imperfection. In this sense the statue looked back at him, judging him, and telling him: “You must change your life.” He knew that, given his shortcomings and his room for personal growth, he himself was a torso too. The realism of his self-image as an incomplete person and a not yet matured poet told him how he could be. Thus, what had been lost in the torso corresponded to his own possibilities that lay ahead. The imperative ‘you must change your life’ was ‘the command from the stone’, as Peter Sloterdijk called it. We all must improve ourselves. We are obliged to make use of our potential and our opportunities to better ourselves, since we are the only beings in the universe who can.