Musannaf Ibn Abi Shayba 23:77

Muhammad ibn Bishr narrated to us, he said: Sa'id narrated to us, from Qatadah, from Anas, that the Prophet of Allah, may Allah bless him and grant him peace, said: "He shall exit the Fire, whoever said 'There is no god but Allah,' and there was in his heart of goodness what weighs a barleycorn." Then he said a second time: "He shall exit the Fire, whoever said 'There is no god but Allah,' and there was in his heart of goodness what weighs a wheat grain."