The bedouins say, “We have believed.” Say, “You have not [yet] believed; but say [instead], ‘We have submitted,’ for faith has not yet entered your hearts. And if you obey Allah and His Messenger, He will not deprive you from your deeds of anything. Indeed, Allah is Forgiving and Merciful.”
The believers are only the ones who have believed in Allah and His Messenger and then doubt not but strive with their properties and their lives in the cause of Allah . It is those who are the truthful.
(QS Al-Hujarat 14-15)