Kāmil al-Ziyārāt > The Ziyārah of Ĥusain (a.s.) Is Obligatory and Every Believer Should Fulfill this Obligation Toward Ĥusain and the Rest of the Imams (a.s.)
Hadith #3

3 حَدَّثَنِي مُحَمَّدُ بْنُ جَعْفَرٍ الرَّزَّازُ قَالَ حَدَّثَنِي مُحَمَّدُ بْنُ الْحُسَيْنِ بْنِ أَبِي الْخَطَّابِ عَنْ أَبِي دَاوُدَ الْمُسْتَرِقِّ عَنْ أُمِّ سَعِيدٍ الْأَحْمَسِيَّةِ عَنْ أَبِي عَبْدِ اللَّهِ (ع) قَالَتْ قَالَ لِي يَا أُمَّ سَعِيدٍ تَزُورِينَ قَبْرَ الْحُسَيْنِ قَالَتْ قُلْتُ نَعَمْ فَقَالَ لِي زُورِيهِ فَإِنَّ زِيَارَةَ قَبْرِ الْحُسَيْنِ وَاجِبَةٌ عَلَى الرِّجَالِ وَ النِّسَاءِ

3. Muĥammad ibn Ja’far Al-Razzāz narrated to me from Muĥammad ibn Ĥusain ibn Abil Khaťťāb, from Abǐ Dāwūd Al-Mustariq, from Um Sa’ǐd Al-Aĥmasiyyah, who said: Abū ‘Abdillāh (Imam Šādiq (a.s.)) asked me, “O Um Sa’ǐd! Do you go to the Ziyārah of the grave of Ĥusain (a.s.)?” I replied, “Yes.” Imam (a.s.) said, “Go to his Ziyārah, for verily going to the Ziyārah of the grave of Ĥusain (a.s.) is WĀJIB (mandatory) on both men and women.”