Barzakh is the intervening period between death and Judgment Day. When a person dies, his soul leaves the physical body, but for the time being he or she is kept in Barzakh, awaiting the final judgment. This world of Barzakh is also having a Paradise and Hell like the Paradise and Hell of the hereafter and the righteous people and believers are lodged in the Paradise of Barzakh, which is called as Wadius Salaam and the sinners and evil doers are chastised in Wadiul Barhut.

A narrator says, “I asked Imam Ja’far Sadig(a.s.), “I have heard you saying that all our Shia will enter Heaven however sinful they may be?” Imam replied, “By Allah, I had truly said, they shall all belong to Heaven.” I asked, “May my life be sacrificed on you, even if their sins are great and in large number?” Imam said, “All ofyou (Shia) shall enter Paradise by intercession of the Holy Prophet (s.a.w.s.) or his successors on Judgment Day. But, by Allah I fear for you the Barzakh.” I asked, “What is Barzakh?” He replied, “Barzakh is the grave. Its duration commences from the time of death until Judgment Day” Thus Barzakh and grave are synonymous, but not in the material aspectSayyidRead this important book for more details on this subject.

Hadith
The Messenger of Allah (s.a.w.s.) said: Before being appointed to the office of prophethood, while grazing the goats of my uncle, sometimes I saw the animals run about in panic,without any apparent cause; when I asked Jibraeel, he said: When the wail of a dead is raised in Barzakh, all can hear it, except Jinns and human beingSayyid(Maniul Akhbar)