And when they exceeded in mockery, they became the most ignorant of the ignorant regarding the impossibility of what is possible. He began the response to their words by denying knowledge from them in the present and the future, without direct observation, in a manner of mockery and derision towards them: "If only those who disbelieved knew". He mentioned the object of the sentence and said: "when", meaning if knowledge were to be renewed for them at the time they hasten towards. He mentioned what was added to that time and said: "they will not be able to stop" (p-422), meaning in it by themselves "from their faces" which are their most honorable parts, "the Fire" in submission - and weakness and inability, "nor from their backs" which are the strongest parts of their bodies. It is known from this that it has surrounded them and that they will not stop from other than these two, by priority. "Nor will they be supported", meaning they will not have any support, apparent or hidden, by themselves or by others. They did not say anything of that disbelief, mockery, and hastening, but they do not know that in a type of knowledge except at the time of occurrence, because there is no sign that decisively determines its timing, nor does it come gradually like others. This is the meaning.