Imam Sajjad's (AS)[1] says about the most difficult moments for every human being.

Imam Sajjad (peace be upon him) says:

The most difficult moments for humans are three stages:

1- When Izrael, the angel of death, enters a person's bed and wants to take his life.

2- When he comes alive from inside the grave and stands up in the desert of Mahshar[2].

3- That time when he is placed in front of the Almighty God - to calculate and review his deeds - and he does not know that he is blessed with. whether it will be heaven and eternal blessings or it will be a path to hell and painful punishment?[3]

 References:

[1] .  Imam Sajjad (AS) has some works as an example is Al-Sahifa al-Sajjadiyya in which has collected a compilation of his supplications in which reflect the picture of the society and the true path of life through the education of the religion, Qur'an, purification of souls and connecting souls to God. Risalat al-huquq (Treatise on Rights) is his other work in which is a short treatise containing duties a human being.

[2] .  the day of judgement where all human being will be present.

[3] .  Sheikh Sadouq, Khisal, p. 119