12. They“disbelieved in their Lord”: their denial of the Hereafter is, in fact, the denial of the Power and Wisdom of Allah. As they say that it is impossible to bring them again to life after their death, it implies that, God forbid, their Allah Who has created them lacks not only power but wisdom, too.
13. As a shackle around the neck is a symbol of imprisonment, the words“shackles upon their necks”have been used here idiomatically to show that they are slaves of ignorance, obduracy, lust and are blind followers of their forefathers. As their thinking is influenced by their prejudices, they cannot believe in the Hereafter and would deny this, though there is every reason to believe that it is inevitable.