Final answer:
Guru Amardas Ji declared Baisakhi, Maghi, and Diwali as the three special days for Sikhs to gather and listen to his teachings.
Step-by-step explanation:
The three special days declared by Guru Amardas Ji for Sikhs to congregate and hear His words are Baisakhi (April 13), Maghi (the first day of Magha, mid-January), and Diwali (the festival of lights in October/November).
These days serve as important occasions for the Sikh community to unite in faith and engage with each other, drawing from the teachings of the Sikh Gurus. They symbolize the collective celebration of Sikh identity and the remembrance of the teachings imparted by the gurus.