Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates that the Prophet (peace and blessings be upon him) said: The people of 'La ilaha illallah' (There is no deity except Allah) will feel no loneliness in the grave, nor when they are raised again (on the Day of Resurrection). It is as though I can see the people of 'La ilaha illallah' even now, shaking the dust off their heads and saying: "All praise belongs to Allah Almighty, who has removed grief from us."
Tabarani recorded it in al-Mu'jam al-Awsat.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأذكار / 16807