Calling people in the markets in accordance with the guidance of the Prophet (peace and blessings be upon him)

Question:
He says: Honorable Shaykh, may Allah grant you success, what is your opinion of the one who says that it is obligatory for the caller to call those in the markets, and that this is what the Prophet (peace and blessings be upon him) did in the market of 'Ukaz?

Answer:
Yes, the caller calls people in any place, in the mosques, in the markets, in any place where they gather; he calls them, admonishes them, and reminds them, because the gathering of people is an opportunity for the caller. Instead of calling them while they are scattered, he calls them while they are gathered.