Anas bin Malik RA reports that Rasulullah SAW said:
"The inability to weep is due to committing excessive sins.
That is due to not fearing Allah -
- which results in the hardness of the heart.
The hardness of the heart is caused by the love of the world." (Musnadul Firdaus)
First of all, it is important to note that the chain of narrators for this Hadith is quite weak. However, the broader implications and applications of the above narration is supported and backed by other traditions. Even by common sense, the spiritual well-being of any human being follows the above chronology. When someone is not afraid of Allah, then he/she will also not be afraid of commiting sins. This in turn hardens the heart which makes it difficult for that person to cry over his/her sins. The love of this world also hardens the heart; and anyone who has love of this world will also find it difficult to cry over his/her sins.