Musnad Ahmad 31:445

'Abd al-Malik ibn 'Amr narrated to us, Hisham narrated to us, from Zayd, from 'Ata' ibn Yasar, from Abu Sa'id al-Khudri, who said: My family sent me to the Messenger of Allah, may Allah bless him and grant him peace, to ask him for food. I came to the Prophet, may Allah bless him and grant him peace, while he was delivering a sermon, and I heard him saying: "Whoever exercises patience, Allah will make him patient. Whoever seeks self-sufficiency, Allah will make him self-sufficient. Whoever seeks chastity, Allah will make him chaste. And no servant has been granted a provision more vast for him than patience."