التفسير التبليغي
(And whoever kills a believer intentionally, his recompense is Hell, wherein he will abide eternally, and Allah has become angry with him and has cursed him and has prepared for him a great punishment.) (93)
(And whoever kills a believer intentionally) Sa'id ibn Al-Musayyab said: This refers to a weapon.
It is narrated from Ibn Abbas, who said: The greatest of major sins are associating partners with Allah (Shirk) and killing a soul that Allah has forbidden.
Killing a soul unjustly is one of the greatest major sins after associating partners with Allah (Shirk), and a believer remains in a state of ease concerning his religion as long as he has not shed forbidden blood.
The crime of murder is a great sin that necessitates punishment in this world and the Hereafter.
(And whoever kills a believer intentionally, his recompense is Hell, wherein he will abide eternally, and Allah has become angry with him and has cursed him and has prepared for him a great punishment.) This verse emphasizes the gravity of killing a believer and magnifies its significance.
Source: التفسير التبليغي