It is narrated from the Prophet of Islam (PBUH) who said:

The heart of a real Muslim does not doubt or betray three elements: Sincerity in deeds for Allah (SWT), good will (giving well-intentioned help and advice) for Muslim leaders in the way of leadership (of Islamic Ummah) , and assist Muslims (wherever and whenever needed)[1].

[1] Kafi, Vol. 1, Page 403.

Source: en.shafaqna.com