Imam has undertaken very useful discussions in his famous book of "an exposition on Forty Hadith" as following:
In the Hereafter, whether it is in the Barzakh (an interval of time between the death of man and his resurrection) or whether on the Last Day, if one’s inner nature, his deeds, and his inner self are really human, his heavenly visage also will be man-like.
But if his deeds are inhuman, he will not possess human form; it will be rather subject to the state of his inner self and his psyche.
For instance, if his inner self is dominated by the power of lust or sensuality (al-quwwah al-shahwiyyah) and animality and brutality overwhelm and govern his inner self, his otherworldly visage will be of a brute and the reign of his inner world would be under the control of one of the beasts, corresponding to that quality of his soul.
If the power of passion or anger conquers one’s inner self and his psyche, his otherworldly appearance will resemble one of the bestial forms, corresponding to that attribute of his nature.
And if the power of imagination and invention is governed by fiendish forces and his inner self is made vicious, governed by the vices like deceit, dishonesty, slandering, backbiting, which are the attributes of Satan, he may undergo a metamorphosis and assume one of the forms of Satan.
Sometimes it is also possible that he would have an appearance that symbolizes two or several vices, Imam further explained.
In that case, a form which does not resemble any of the brutes, but an unusual and queer form, with which cannot be compared the most terrible and ugliest monster in the world, will be acquired by him.
Read more: