It has been related that once Imam Sadeq (AS) was ill. The Imam ordered someone to be hired to go to the tomb of Imam Hussein and to pray for him. The hired man expressed surprise, for to him there was no difference between the two Imams. Therefore he asked for the reason. Imam Sadeq (AS) said:
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89. “This man is right but he does not know that God has specified lands where Duas are answered and the Holy shrine of Imam Hussein is one of them.”