Hawzah News Agency – The merciful prophet of Islam (pbuh) says:

لكلِّ شَي‏ءٍ اُسٌّ، واُسُّ الإيمانِ الوَرَعُ.

'For everything there is a basis, and the basis of faith is piety.'

Source: Kanz al-Ummal, no. 7284