بسم الله الرحمن الرحيم
Sheikh Muhammad Bazmool said about Allah’s statement:
يأيها الذين آمنوا اتقوا الله و آمِنوا بِرسوله يؤتكم كفلَين من رحمته ويجعل لكم نورًا تمشُون به و يغفر لكم والله غفور رحيم
“O you who believe fear Allah and believe in His messenger. He will give you a double portion from His mercy and will make a light with which to walk and will forgive you, and Allah is Oft Forgiving and Merciful.” [Al-Hadid: 28]
Allah said -He will give you a double portion of mercy- meaning He will give two tremendous rewards, so what are they? Allah spoke vaguely about the two in magnification of this reward. As it is a reward that you are unable to outline by way of your speech nor by way of your perception. It is a reward from Allah for whoever adopts the religion and clings to it.
Source: شرح فضل الإسلام
Translated by Najeeb Al Anjelesi