He said, I also heard him say, "Allah named Madinah Taybah."
قال وسمعته يقول إن الله تبارك وتعالى سمى المدينة طيبة
Its isnad is sahih. The first part of it appeared earlier at 20684, and the second part, that Allah named Madinah Taybah, was narrated by Bukhari in meaning, 4/88, no. 1872 Fath, and Muslim, 2/1007, no. 1385, with similar wording, and Tirmidhi, 5/239, no. 3028, who said, hasan sahih.