Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "Whoever guards these obligatory prayers will not be written among the heedless. And whoever recites one hundred verses in a night will also not be counted among the heedless, or he will be written among the obedient." And the Messenger of Allah (peace and blessings be upon him) said: "The best and most exalted words are four: « سُبْحَانَاللَٰه » 'Allah is Pure,' and « الحَمْدُلِلَٰه » 'All praise is for Allah,' and « لَاإِلٰهَإِلَّا الله » 'There is no deity worthy of worship except Allah,' and « اللهُأَكْبَرُ » 'Allah is the Greatest.'"
Hadith Referenceصحيح ابن خزيمه / جماع أبواب صلاة التطوع بالليل / 1142