Shoghi said "This work is killing me!" when he was in London during the last days of his life and ill due to Influenza.

While he was working, he repeated once again the words I had so often heard him say during the last years of his life: “This work is killing me! How can I go on with this? I shall have to stop it. It is too much. Look at the number of places I have to write down. Look how exact I have to be!” He was tired when it was finally done and went back to his bed, where he sat and read reports.

(The Priceless Pearl, Rúhíyyih Rabbani)