Musnad Ahmad 2:272

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us. And Hajjaj said: Shu‘bah narrated to me, he said: I heard Qatadah narrating from Sa‘id ibn al-Musayyib, from Ibn ‘Umar, from his father, from the Prophet, may Allah bless him and grant him peace, who said: "The deceased is punished in his grave for what is wailed over him." And Hajjaj said: "For the wailing over him."