Musnad Ahmad 904:1

'Abd al-Razzaq narrated to us, Hisham informed us, from Ibn Sirin, from a woman who was called Raja', she said: I was with the Messenger of Allah, may Allah bless him and grant him peace, when a woman came to him with a son of hers. She said: "O Messenger of Allah, supplicate to Allah for me for blessing in him, for three [of my children] have died." The Messenger of Allah, may Allah bless him and grant him peace, said to her: "Since you have accepted Islam?" She said: "Yes." The Messenger of Allah, may Allah bless him and grant him peace, said: "A fortified shield." A man said to me: "Listen, O Raja', to what the Messenger of Allah, may Allah bless him and grant him peace, is saying."