What is the authenticity of the Hadith: "Whoever says: 'There is no god but Allah, and Allah is the Greatest; there is no god but Allah alone; there is no god but Allah, and He has no partner; there is no god but Allah, to Him belongs the dominion, and to Him belongs the praise; there is no god but Allah, and there is no might and no power except with Allah...' his sins will be forgiven"?

This hadith was narrated by An-Nasa'i from Abu Hurairah that the Messenger of Allah (peace and blessings be upon him) said: "Whoever says: 'La ilaha illallah, wallahu akbar (There is no god but Allah, and Allah is the Greatest). La ilaha illallah wahdahu (There is no god but Allah alone). La ilaha illallah, wa la sharika lah (There is no god but Allah, and He has no partner). La ilaha illallah, lahul-mulku, wa lahul-hamd (There is no god but Allah, to Him belongs sovereignty and all praise). La ilaha illallah, wa la hawla, wa la quwwata illa billah (There is no god but Allah, and there is no might and no power except with Allah).' He counted them as five on his fingers, then said: 'Whoever says them in a day, or in a night, or in a month, then dies on that day, or in that night, or in that month; his sins will be forgiven for him.'" Al-Albani authenticated it due to supporting narrations, so there is no harm in acting upon it.