مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3091
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
Ibn 'Abbas narrated that he heard The Messenger of Allah (ﷺ) say, as he was delivering a speech: “Whoever cannot find an izar (waist wrapper) but can find pants, let him wear them; whoever cannot find sandals but can find Khuffain, let him wear them."
Musnad Ahmad 3115Its isnad is saheeh, al-Bukhari (1843) and Muslim (1178)]