Imran bin Husayn reported,

The Prophet ﷺ asked a man, "Did you fast anything during the final days of this month?" meaning Shaban.The man replied, "No."So he said to him, "When you have finished the fast of Ramadan, then fast a day or two."Shuba was the one who was uncertain about it. He said, "I think he said two days."

Muslim 2754

Sahih

و حدثني محمد بن قدامة ويحيى اللؤلؤي قالا أخبرنا النضر أخبرنا شعبة حدثنا عبد الله بن هانئ ابن أخي مطرف في هذا الإسناد بمثله

مسلم 2754صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Muslim
Book
Fasting
Chapter
Fasting the last days of Shaban
Numbering
Darussalam 2754
Muslim 2754