The Messenger of Allah ﷺ used to fast until we would say he never broke his fast, and he would go without fasting until we would say he never fasted.
حدثنا محمد بن عبيد حدثنا عثمان بن حكيم قال سألت سعيد بن جبير عن صوم رجب كيف ترى فيه قال حدثني
أن رسول الله ﷺ كان يصوم حتى نقول لا يفطر ويفطر حتى نقول لا يصوم
Its isnad is sahih, and it is a repeat of 1998, and it will come with this same isnad at 3011.