Hadhrat Ibn Ata Iskandari (nawarallahu marqaduhu) says,
“The deeds of the servants are the external forms
while Ikhlaas is the soul (rooh) for deeds.”
The righteous deeds of the servant, e.g. Salaat, Saum, Hajj, Zakaat, etc., devoid of ikhlaas are like a dead body without soul. Ikhlaas, i.e. the opposite of riya (show) and nafsaani desire, and their elimination from an action, is like the rooh and life. If the action is accompanied by ikhlaas, it will have life in it. On the contrary, if the action is devoid of ikhlaas and is rendered to show others or to derive personal pleasure, it will be like a lifeless body without benefit in the akhirah.
[“Ikhmaal Ash-Shiyam”, Maulana Muhammad Abdullah Gangohi]