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

إنَّ مَنزِلَةَ القلبِ مِن الجَسَدِ بمَنزِلَةِ الإمامِ مِن الناسِ.

'The status of the heart to the body is the same as that of a leader among people.'

Source: Ilal al-Sharai, p. 109, no. 8