Hawzah News Agency – Imam al-Sadiq peace be upon him says:

إنَّ مِن التَّواضُعِ أن يَجلِسَ الرّجُلُ دُونَ شَرَفِهِ.

'Humbleness is when a man sits in a place lower than his rank.'

Source: al-Kafi, v. 2, p. 123, no. 9