(Lo! those who disbelieve the revelations of Allah) i.e. Muhammad (pbuh) and the Qur'an, (Allah guideth them not) to His religion, i.e. He does not guide those who do not deserve to be guided; it is also said that this means: He does not guide them to the right proof nor save them from the Fire (and theirs will be a painful doom) a severe chastisement.