We used to pledge allegiance to the Prophet ﷺ to listen and obey, and he would prompt us to add, "as much as you are able."
حدثنا حفص بن عمر حدثنا شعبة عن عبد الله بن دينار
كنا نبايع النبي ﷺ على السمع والطاعة ويلقننا فيما استطعت
Bukhari transmitted it in the Book of Rulings, in the chapter "How Should the Ruler Take the Pledge from the People?" hadith no. 7202, and Muslim transmitted it in the Book of Governance, in the chapter "The Pledge to Hear and Obey According to One's Ability," hadith no. 1867, from the hadith of Abdullah bin Dinar with this same wording.