It has been narrated that the Prophet (Sallallahu Alaihi wa Sallam) said: "Whoever asks blessings for me at my grave, I hear him, and whoever asks blessings upon me from afar, it is conveyed to me" .
Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
The Hadith mentioned in the question is reported by al-Baihaqi in his book: 'Shuab al-Iman'. According to al-Baihaqi , Abu Hurairah narrated the Prophet (Sallallahu Alaihi wa Sallam) said: "Whoever invokes blessings on me at my grave, I hear him and whoever invokes blessing on me in a remote place, it is reported to me" .
But this Hadith is weak as graded by Imam Ibn Katheer in his Tafseer (explanation of Qur'an). al-Mannawi said: ' al-Aqili said, this Hadith has no foundation' . Ibn Dihyata said: 'It is rejected and nobody except Muhammad Ibn Marwan al-Suddi narrated it and he was known to be a liar. So, this Hadith is not authentic and thus it is rejected as it is fabricated.
Allah knows best.
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