Sulaiman(A sunni brother): You people venerate the graves of Ahle Bayt (a.s.) and yearn to visit them (ziarat). Isn’t it haraam?
Ja’far(A shia brother): We believe that the traditions used by those who prohibit the ziarat of graves are incorrect. Or they have not understood the context of the traditions. And it has been the practice of the Messenger of Allah (s.a.w.s.) to visit graves. He visited the grave of his dear mother and wept upon it. His companions joined him in the lamentation. (Sahih Muslim 2:671). In the same way Fatemah Zahra (s.a.) visited the tomb of her father. Muslims throughout the ages have visited the tomb of the Messenger of Allah (s.a.w.s.) and the graves of the Imams of Ahle Bayt (a.s.) that are situated in the Baqi cemetery of Madinah.
Therefore if you prohibit the visitation to graves it will go against some authentic traditions, like,
"Verily, I had restrained you from visiting the graves. Now, visit them. Certainly, it reminds one of the Hereafter."
(Sunan Tirmidhi, Vol.3, Pg. 370)
Since the earliest times it had been custom of people (Muslims) to visit graves.
Sulaiman: However, you people bestow on them the position of divinity and respect them greatly. You also build upon them places of worship?
Ja’far: Certainly, the Almighty Allah has ordered us to consider the place where Ibrahim (a.s.) stood, as a place of worship.
The Holy Quran says,
"Appoint for yourselves a place of prayer on the standing-place of Ibrahim."
(Surah Baqarah 2:25)
Similarly, the cave where the ‘People of the Cave’ took shelter was also made into a place of worship. As mentioned in the following ayat,
"When they disputed among themselves about their affair and said: Erect an edifice over them — their Lord best knows them. Those who prevailed in their affair said: We will certainly raise a masjid over them."
(Surah Kahf 18.21)
Moreover, the Messenger of Allah (s.a.w.s), the Ahle Bayt (a.s.) and the Muslim leaders have till this day circumambulated around Hijr-e-Ismail (when they go Hajj or Umrah). It is actually the grave of Hazrat Ismail (a.s.), his mother Hajra (s.a.), his daughters, and some other Prophets (a.s.).
Now, if it is haraam to visit, or to convert into places of worship, the graves of prophets and messengers and the righteous servants of Allah, why do we find the Holy Prophet (s.a.w.s.) following such a practice? And if it is the practice of the Messenger of Allah (s.a.w.s), then what restrains us from following this practice (Sunnat)?
Sulaiman: But this is ‘shirk’ (Polytheism- associating someone or something with Allah)!
Ja’far: I said, ‘for the servants of Allah’, then how can it be shirk when the Messenger of Allah (s.a.w.s) has followed this practice? Also, have you ever seen any Muslim praying towards a grave while considering it as a Qibla (direction faced during prayers)? Whenever you see people praying at the tombs, know that they are engrossed in the worship of Allah. They have not changed their deity. They worship Allah at this place because it is a blessed and purified place. The place is associated with one of the beloved ones of Allah. It is a sign that reminds us of this great personality who is the dweller of this place.
It is haraam according to shariat to worship anyone other than Allah at the grave. Such a thing is not found in the Islamic world. The doubters and those who misinterpret have such wrong notions, which are of no value.
Sulaiman: Are you not content with visiting the graves, that you also sacrifice animals as (vow) nazr?
Ja’far: You will never find anyone slaughtering a sheep or goat at the grave so that its blood flows around the grave. It is a concocted story and an attempt to distort the definition of ‘nazr’?
‘Nazr’ (dedication) is of two types. One of them is the nazr whereby a Muslim performs it for Allah but gifts its sawaab (reward) by the permission of the Almighty. Included in this type are worship-acts like prayers, fasts, charity and sacrifice for Allah. The second type of Nazr is for the Prophet (s.a.w.s.) or a righteous person from among the Muslims. Like the construction of a Mosque, digging of wells, spending on orphans, with the intention of serving Allah the Almighty, the One without partners. After performing such acts, one gifts the rewards to the Holy Prophet (s.a.w.s.) or a righteous personality.
The Messenger of Allah (s.a.w.s) said to the girl, who had vowed to do something for her father,
"Fulfill your vow."
(Sunan Abi Dawood, Vol. 2, Pg. 80)
Similarly, a man had vowed to slaughter a camel on a particular spot, not having an idol or any association with the customs of Ignorance (jahiliya). When he asked the Messenger of Allah (s.a.w.s) about its permissibility, he said,
"Fulfill your nazr (vow.)"
Now, as far as the slaughter of goat on the grave is concerned (if such a practice exists). It consists of gifting the sawaab of this action (the slaughtered meat is distributed to the poor and other people) on behalf of the dweller of the grave. It is a worship act for Allah, not for the person on whose grave it is performed. But if an animal is not sacrificed according to the rules of shariat, it is haraam to eat its meat. The rules for slaying an animal include the pronouncement of Bismillah and Allaho Akbar and facing the Qibla (Holy Ka’ba). One who is slaughtering must be a Muslim. Apart from this, while taking a vow, the person should have uttered (By Allah I vow to sacrifice an animal as nazr). Verily, all Muslim Scholars are unanimous that it is permissible to gift the sawaab of such nazr to a departed soul.