﴿ وَإِذْ قَالَتْ أُمَّةٌۭ مِّنْهُمْ لِمَ تَعِظُونَ قَوْمًا ۙ ٱللَّهُ مُهْلِكُهُمْ أَوْ مُعَذِّبُهُمْ عَذَابًۭا شَدِيدًۭا ۖ قَالُوا۟ مَعْذِرَةً إِلَىٰ رَبِّكُمْ وَلَعَلَّهُمْ يَتَّقُونَ ﴾

“And whenever some people among them asked [those who tried to restrain the Sabbath-breakers], "Why do you preach to people whom God is about to destroy or [at least] to chastise with suffering severe?" -the pious ones would answer, "In order to be free from blame before your Sustainer, and that these [transgressors, too,] might become conscious of Him."”

It is a sin to do anything which God has prohibited. But to perform a prohibited act by attempting to legalize it through some trick amounts to adding insult to injury. By violating the rule of the Sabbath, the Jews had committed a double sin. Such people must suffer divine retribution; that is, they are deprived of the bounties which God has set apart for human beings alone. In this world such people fall from the level of humanity to the level of the animals.