The Messenger of Allah (ﷺ) as saying: There is no virtue more to the liking of Allah in any day than in these days, that is, the first ten days of Dhu al-Hijjah. They (the Companions) asked: Messenger of Allah, not even the struggle in the path of Allah (Jihad) ? He said: (Yes), not even the struggle in the path of Allah, except a man who goes out (in the path of Allah) with his life and property, and does not return with any of them.

I never saw the Messenger of Allah (ﷺ) fasting during the first ten days of Dhu al-Hijjah.