The foundational teaching of Islam is Tawheed (the Oneness of Allah). This means that it is imperative to only worship Allah and not associate anyone or anything else with Allah in worship.
Regrettably, the virus of “grave worship” has infected parts of the Muslim Ummah due to widespread ignorance and the misguided Ulema of false sects like the Barelwis and Deobandis. While the former openly advocate grave worship and claim that the deceased have the ability to hear and answer supplications, the latter (Deobandis) pretend that they are monotheists and claim to disavow grave worship.
However, the reality is, as I have proven repeatedly on this blog, that the Deobandis are no different than the Barelwis when it comes to grave worship and veneration. The most authentic book of Deobandi creed is called Al-Muhannad alal-Mufannad. All Deobandi Ulama are required to approve of this book which is the basic manual of Deobandi creed. In this book, the Arab Ulama from Hijaz ask various questions pertaining to doctrine to the Deobandis. In their answer to the eleventh question, the Deobandis state:
واما الاستفادة من روحانية المشالئخ الاجلة ووصول الفُيوض الباطنية من صدورهم او قبورهم فيصح
اب رہا مشائخ کی ورحانیت سے استفادہ اور ان کے سینوں اور قبروں سے باطنی فیوض پہنچنا سو بیشک صحیح ہے
Translation: “As for obtaining benefit from the spirituality of the Mashayikh (Sufi elders), and attaining inner Faid (spiritual benefit) from their chests and graves, then that is undoubtedly correct.”
Reference: Al-Muhannad alal-Mufannad; p.45