Ibn Majah

Benefits and Issues:

➊
The meaning of a dead heart is that just as a dead person has no sense of anything, similarly, a heedless person has no sense of benefit or harm regarding his Hereafter.

➋
When the heart becomes dead, instead of softness, hardness develops in it, and instead of mercy, feelings of oppression arise.
Love for righteousness and hatred for sin come to an end.

➌
Cheerfulness is a good habit and is desirable according to the Shari‘ah, but to be indifferent to everything and to spend all the time in laughter, jest, and amusement is a sign of heedlessness and a dead heart.
It is necessary to consider the troubles of others as your own and to participate in the pain and suffering of others.