Tirmidhi

1:
This hadith indicates that it is permissible to kiss a deceased Muslim and to weep over them. As for those hadiths in which weeping is prohibited, they should be understood as referring to such weeping that involves wailing and lamentation.

Note:

(See:
Taraaji‘ al-Albani 495)

Benefits and Issues:
A Muslim is never impure (najis), neither during life nor after death.
There is nothing objectionable in kissing one’s beloved deceased.
And shedding tears out of grief for them is a natural matter.
There is no harm in this.

Benefits and Issues:
➊
Hazrat Uthman bin Maz'oon was among the eminent Companions (radi Allahu anhum ajma'een). Before him, only thirteen individuals had embraced Islam. He was honored with both the migration to Abyssinia and the migration to Madinah. He also participated in the Battle of Badr. Nawab Waheed uz-Zaman Khan has written that Hazrat Uthman bin Maz'oon was also a milk-brother of the Messenger of Allah (sallallahu alayhi wa sallam).

➋
Weeping and shedding tears due to grief is not contrary to patience. Rather, it is a sign of mercy and tenderness of heart.

➌
The aforementioned narration is weak in its chain of transmission. Kissing the deceased is not established from the Messenger of Allah (sallallahu alayhi wa sallam); however, Hazrat Abu Bakr as-Siddiq (radi Allahu anhu) kissed the Prophet (sallallahu alayhi wa sallam) after his passing, as will be mentioned in the following narration.