Musnad Ahmad 31:104

Shu'ayb ibn Harb narrated to us, Hisham ibn Sa'd narrated to us, Zayd ibn Aslam narrated to us, from 'Ata' ibn Yasar, from Abu Sa'id al-Khudri, who said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "Whoever seeks to be patient, Allah will make him patient. Whoever seeks to be self-sufficient, Allah will make him self-sufficient. And whoever seeks to be chaste, Allah will make him chaste. And I do not find for you any provision more expansive than patience."