فَتُوبُواْ إِلَى بَارِئِكُمْ فَاقْتُلُواْ أَنفُسَكُمْ ذَلِكُمْ خَيْرٌ لَّكُمْ عِندَ بَارِئِكُمْ فَتَابَ عَلَيْكُمْ إِنَّهُ هُوَ التَّوَّابُ الرَّحِيمُ

(So turn in repentance to your Creator and kill yourselves (the guilty), that will be better for you before your Creator." Then He accepted your repentance. Truly, He is the One Who accepts repentance, the Most Merciful.) 2:54 As for the humiliation mentioned in the Ayah, it pertains to the disgrace and humiliation that the Jews suffered in the life of this world. Allah's statement,

وَكَذَلِكَ نَجْزِى الْمُفْتَرِينَ

The verse 153 speaks of the people who repented to Allah for their sin after the admonitions of their Prophet, and fulfilled the formidable condition of killing each other for their forgiveness. They killed each other as was stipulated in the command of Allah for their forgiveness by Allah. The Prophet Musa (علیہ السلام) called them to him and informed them that Allah had accepted their repentance. The people killed in this combat were awarded martyrdom while those who survived were forgiven by Allah. This implies that those who get themselves involved in sinful acts, if repent to Allah and correct their belief, Allah forgives them in His mercy with no regard to the gravity of the act. It is, therefore wise to turn to Allah in repentance instantly after every sinful act.'