Hazrat Tamim Dari states that on the Day of Judgment, the very first account will be taken of the obligatory prayers. If they are found complete, it is fine; but if they are not complete, it will be said: "See if he has any voluntary prayers." The deficiency in the obligatory prayers will be fulfilled from his voluntary prayers. If the obligatory prayers are not complete and there are no voluntary prayers either, then that person will be seized and thrown into Hell.