Trường Bộ Kinh (Digha Nikaya) 1:442
SUJATOAtha kho bhagavato vassūpagatassa kharo ābādho uppajji, bāḷhā vedanā vattanti māraṇantikā.
After the Buddha had commenced the rainy season residence, he fell severely ill, struck by dreadful pains, close to death.