"He who listens to his body, knows when he needs rest."
Translation:Wer auf seinen eigenen Körper hört, weiß, wann er Ruhe braucht.
I thought the w- joiner words (e.g. wessen, wer, wem), as in other cases, are used in questions when the person(s) referred to is/are unknown. Therefore, I used the d- joiner word here 'der', and wrote, "Er, der auf seinen Körper hört, weiß, wann er Ruhe braucht." Is this impossible? or is it rather that such a formulation is avoided and in such cases (proverbs, for example) the ambiguous wer is used as subject....? thanks for any help.
You should note that the aktivitat is at the end (I am not sure how to say this in english). If it was a question it would take second position after the question word wer.