Sayyiduna Abdul Rahman bin Awf (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Whoever recites this every day in the morning and in the evening:
'La ilaha illallahu wahdahu la sharika lahu, lahul-mulku wa lahul-hamdu, yuhyi wa yumitu, wa huwa hayyun la yamutu, biyadihil-khayr, wa huwa 'ala kulli shay'in qadir'
(There is no deity except Allah Almighty; He alone is the deity, He has no partner; to Him alone belongs the dominion and to Him alone belongs all praise; He gives life and He gives death; He is Ever-Living and will never die; all good is in His hand, and He has power over all things)
(the Prophet, peace and blessings be upon him, says:) then that person's sins are forgiven, even if they are more than the foam of the sea."
Al-Bazzar recorded it; its chain contains Abu Bakr bin Abdullah bin Abi Sabrah, who is matruk (abandoned).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأذكار / 16987