On the other hand, going to the grave to offer Tawbah (repentance) and seek forgiveness is baseless; it is an impermissible and abominable act of Bid`ah (innovation in religion) and a means to Shirk (associating others in worship with Allah), such as asking for intercession, curing a patient, attaining victory over enemies, and asking for Du`a' (supplication). All this is impermissible, for the Prophet (peace be upon him) did not do these things, nor any other persons after their death.
It is impermissible to invoke or intercede to a deceased person, whether he is the Prophet (peace be upon him) or any other person. However, this used to be done during his lifetime, like those who used to ask for his intercession by saying: O Messenger of Allah! Intercede with Allah for me to forgive me, cure my patient, return back the absent, give me so and so.
The same also occurs on the Day of Judgment after Resurrection, when the Mu'minun come to Adam to ask him to intercede for them with Allah to start judgment among them, but he apologizes and turns them over to Nuh (Noah). They go to Nuh but he also apologizes and turns them over to Ibrahim (Abraham) who again apologizes to them and turns them over to Mussa (Moses), who also apologizes and turns them over to `Eissa (Jesus), who turns them over to Muhammad (peace be upon him).
After they all apologize for not interceding, Muhammad (peace be upon them) says: I am fit for that, then he proceeds to prostrate under the `Arsh (Allah's Throne), praises His Lord with words of praise inspired by Allah (Exalted be He), which he does not yet know. He will be told: "Raise your head, speak, and you will be heard, ask and you will be answered, intercede and your intercession will be accepted."
Therefore, the Prophet (peace be upon him) will continue interceding for the people of the scene until He (Exalted be He) judges among them, and he (peace be upon him) will intercede for the people of Jannah (paradise) until they enter it. So, this will happen because he (peace be upon him) will be present, but in the Barzakh (period between death and the Resurrection), after his death; he should not be asked to intercede, cure a patient, return an absent person back and such things.
The same applies to other deceased people, for they should not be asked any such things, rather, we should supplicate to and seek forgiveness from Allah (Exalted be He) for them if they are Muslims. This should be sought from Allah alone, such as to say: O Allah! Accept your Prophet's intercession (peace be upon him) for me; O Allah cure my patient; O Allah grant me victory over my enemy and so on.
Invoke Me, [i.e. believe in My Oneness (Islâmic Monotheism) and ask Me for anything] I will respond to your (invocation).
And when My slaves ask you (O Muhammad ﺻﻠﻰ ﺍﷲ ﻋﻠﻴـﻪ ﻭﺳـﻠﻢ) concerning Me, then (answer them), I am indeed near (to them by My Knowledge). I respond to the invocations of the supplicant when he calls on Me (without any mediator or intercessor).
But no, by your Lord, they can have no Faith, until they make you (O Muhammad ﺻﻠﻰ ﺍﷲ ﻋﻠﻴـﻪ ﻭﺳـﻠﻢ) judge in all disputes between them
This is general, for it is impermissible for Muslims to deviate from
Allah's Shari`ah, on the contrary, they should rule according to it in everything, regarding acts of worship, transactions, and all religious and worldly affairs, for it is comprehensive.
Do they then seek the judgement of (the days of) Ignorance? And who is better in judgement than Allâh for a people who have firm Faith.
And whosoever does not judge by what Allâh has revealed, such are the Kâfirûn (i.e. disbelievers of a lesser degree as they do not act on Allâh's Laws). And whosoever does not judge by that which Allâh has revealed, such are the Zâlimûn (polytheists and wrongdoers of a lesser degree). And whosoever does not judge by what Allâh has revealed (then) such (people) are the Fâsiqûn [the rebellious i.e. disobedient (of a lesser degree) to Allâh].
These Ayahs are common to all things, which people disagree and dispute about. This is why Allah (Glorified be He) says: But no, by your Lord, they can have no Faith meaning Muslims and others until they make you (O Muhammad ﺻﻠﻰ ﺍﷲ ﻋﻠﻴﻪ ﻭﺳﻠﻢ) judge meaning Muhammad (peace be upon him), and this happens by making him (peace be upon him) judge during his life and rule by his Sunnah after his death, for ruling according to his Sunnah is to judge by the Qur'an and the Sunnah: in all disputes between them meaning in all that which they dispute about.
That is what they should do to refer to the Noble Qur'an and the Messenger (peace be upon him) for judgment among them during his life and after his death as well as following his Sunnah, which represents a declaration and interpretation of the meanings of the Qur'an.