they swear by allah with solemn oaths that allah will not resurrect those who die. yes indeed it is a promise binding upon him but most people do not know so that he may clarify for them what they differ about and that the faithless may know that they were liars.
وأقسموا بالله جهد أيمانهم لا يبعث الله من يموت بلى وعدا عليه حقا ولكن أكثر الناس لا يعلمون ليبين لهم الذي يختلفون فيه وليعلم الذين كفروا أنهم كانوا كاذبين