Al-Baqara • EN-TAZKIRUL-QURAN
﴿ وَإِذْ قَالَ مُوسَىٰ لِقَوْمِهِۦ يَٰقَوْمِ إِنَّكُمْ ظَلَمْتُمْ أَنفُسَكُم بِٱتِّخَاذِكُمُ ٱلْعِجْلَ فَتُوبُوٓا۟ إِلَىٰ بَارِئِكُمْ فَٱقْتُلُوٓا۟ أَنفُسَكُمْ ذَٰلِكُمْ خَيْرٌۭ لَّكُمْ عِندَ بَارِئِكُمْ فَتَابَ عَلَيْكُمْ ۚ إِنَّهُۥ هُوَ ٱلتَّوَّابُ ٱلرَّحِيمُ ﴾
“and when Moses said unto his people: "O my people! Verily, you have sinned against yourselves by worshipping the calf; turn, then. in repentance to your Maker and mortify yourselves; this will be the best for you in your Maker's sight". And thereupon He accepted your repentance: for, behold, He alone is the Acceptor of Repentance, the Dispenser of Grace.”
True piety is to worship God alone, to believe in Him though one has not seen Him, to live in fear of Judgement Day, to subsist on the pure things of the earth, to prevent whomsoever one can from falling into sin. It is those who adopt this way of life who will be successful in the next world.