Refutation of Shirk and Kufr with Loud Dhikr

From Sawwar ibn Shabib al-A`raji:

I was sitting in Ibn `Umar’s house when a man came and said: “O Ibn `Umar! There are groups of people bearing witness against us and attributing to us kufr and shirk.” Ibn `Umar replied: “Woe to you! Did you not say: ‘La Ilaha IllAllah‘?!” Whereupon the entire household began to say La Ilaha IllAllah until the house was shaking. (Imam Abu al-Qasim ibn `Asakir narrates in Tabyin Kadhib al-Muftari)