Whenever we pledged allegiance to the Messenger of Allah ﷺ to listen and obey, he would prompt us to add, "to the best of your ability."
حدثنا عفان حدثنا شعبة عن عبد الله بن دينار قال سمعت
كنا إذا بايعنا رسول الله ﷺ على السمع والطاعة يلقننا هو فيما استطعت
Its isnad is sahih, and it is a repetition of 5531. His saying, "as much as you are able," we have established several times previously with the ta pronounced with fatha, as addressed to the listener, and its explanation is clear. Nawawi explained it in his commentary on Muslim as having the ta pronounced with damma, referring to the speaker, meaning he says to him, "Say, as much as I am able." In the Sahih Muslim printed in the Istanbul edition, 6:29, it is marked with both damma and fatha together, allowing for both readings. Its editor said in his footnote, "In some of the manuscripts in our possession, it occurs as 'astataa'tu' with the ta pronounced with fatha, and this is the clear reading."