“And whatever you spend of expenditures or make of vows – indeed, Allah knows of it. And for the wrongdoers there are no helpers”. (Quran 2: 264)
The vow that perhaps some people make with Allah that if so and so thing is done I will do so and so is what is known as a Vow (nadhar).
The Messenger of Allah discouraged the believers from making such nadhar or vows, for the truth is that the vow itself has absolutely no bearing on what has already been destined by Allah. Humble supplication with charity or good deeds is encouraged. But even if one make vow (nadhar/mannat) should not be adament about to be fulfilled. As it is totally in the hand of Allah who is All-knowing and Omnipotent. “..whether you conceal what is in your hearts or bring it into the open, God knows it: for He knows all that is in the heavens and all that is on earth; and God has the power to will anything.” – (Quran 3:29)
The Prophet pbuh said, “Allah, The High and Exalted, Says, ‘The Vow (nadhar) does not bring about for the son of Adam anything I have not Decreed for him, but his (vow) nadhar may coincide with what has been decided for him, and by this way I cause a miser to spend of his wealth. So he gives Me (spends in charity) for the fulfillment of what has been Decreed for him what he would not give Me before but for his vow!” (Sahih Al-Bukhari)
The Prophet pbuh discouraged the making of nadhar (vows) and said, “It (a vow) does not prevent anything (that has to take place), but (through the vow) the property of a miser is spent (taken out) with it.” (Al-Bukari)
Having said that making a nadhar or a vow is discouraged in Islam and one should not make conditions with their Lord in their supplications, Allah has appreciated and praised those believers who fulfill their nadhars or vows that they have made with their Lord! Making a promise only to Allaah is a kind of vow (mannat) and an oath (yameen) and it should be fulfilled. This indicates that whoever makes a vow to observe an act of worship/ charity/fast/piligrimage has to fulfil it, because a promise or covenant is a vow and an obligation, it is only made with Allah.
If one wishes to give charity then he should not suspend it upon making an oath or a vow. By doing so the impression is given that his wish is the real aim whilst the charity is secondary. Rather he should spend in the path of Allah without suspending it on an oath. One should abstain from putting conditions or making a nadhar or vow with their Lord when one desires a thing but rather remain constant in doing good deeds and whenever ones heart desires anything, one should request and beg their Lord in supplications with absolute and total awe, humility, and hope for the Lord responds to each and every supplication made by His believing slaves.
But if anyone visits the Shrine (dargah) assuming that those dead and buried in their graves can hear and solve their problem, trying to makes a mannat (vow) or nadhar (nazar) with Saint of shrine or person invoking or asking other than Allah then the person is commiting Shirk (associating partner other than Allah because they are also the slaves of Allah so we can’t ask dead person for help). Which is prohibited and Haraam in islaam. It will count as shirk in the Sight of Allah !
Allaah says : “And of them are some who made a covenant with Allaah (saying): ‘If He bestowed on us of His Bounty, we will verily, give Sadaqah (Zakaah and voluntary charity in Allaah’s Cause) and will be certainly among those who are righteous” [al-Tawbah 9:75]
Allah knows best.