I rarely saw the Messenger of Allah ﷺ not fasting on Friday.
حدثنا إسحق بن منصور أنبأنا أبو داود حدثنا شيبان عن عاصم عن زر
قلما رأيت رسول الله ﷺ يفطر يوم الجمعة
[Its isnad is hasan] Reported by Abu Dawud Sijistani, in the Book of Fasting, Chapter: On fasting three days from each month, Hadith 2450, from the hadith of Abu Dawud Tayalisi through it. Tirmidhi said, "Hasan gharib."