What is the ruling on the adhan inside the mosque?

The Shaykh : And I will add a note for you: the adhan of the mu'adhdhin inside the mosque is a religious innovation (bid'ah). The mu'adhdhin should be on the roof of the mosque or in a minaret, not in the kind of minarets that are like cloud-piercing towers. Rather, it is obligatory for the mu'adhdhin to be seen with his person, not just by his voice. These are Islamic symbols that people kill off because of their heedlessness and their lack of understanding of the wisdom of legislation, or rather, the rulings of the Shari'ah. The mu'adhdhin may see in the Sunnah the distinction between the mu'adhdhin and the one who gives the iqamah. The one who gives the iqamah for the prayer does so inside the mosque, whereas the mu'adhdhin calls the adhan from the roof of the mosque. Now, there is no difference between the mu'adhdhin and the one who gives the iqamah!