Musnad Ahmad 31:423

Muhammad ibn Ja'far narrated to us, Sa'id narrated to us, from Qatadah, from Abu Nadrah, from Abu Sa'id al-Khudri, who said: "We went out with the Messenger of Allah, may Allah bless him and grant him peace, when twelve nights remained of Ramadan, on his expedition to Hunayn. Some groups of people fasted, and others broke their fast. The one who fasted did not criticize the one who broke his fast, nor did the one who broke his fast criticize the one who fasted."