Are the number of days for Eid al-Fitr and Eid al-Adha specified in the Qur'an and Sunnah?

The determination of the days of Eid al-Fitr and Eid al-Adha came in the noble Prophetic Hadith. Eid al-Fitr is one day, and Eid al-Adha is followed by three days, which are the days of Tashreeq, as stated in the Almighty's saying: "And remember Allah during [specific] numbered days," and the Prophet's (peace be upon him) saying: "The Day of Fitr, the Day of Nahr, and the days of Tashreeq are our Eid, the people of Islam."