Although the signs of Allah’s existence are obvious, disbelivers find pretexts not to believe and ask for miracles from Allah. The Prophet Muhammad’s (saas) people also asked him to work miracles in order not to adhere to him; the reason why such people asked for miracles was not to have faith or to deepen their faith; it was simply a pretext for their unwillingness to submit themselves to Allah. Allah commanded the Prophet Muhammad (saas) to say the following to these people:

They have solemnly sworn by Allah that if a Sign be given them, they will believe in it. Say: “The Signs are vouchsafed by Allah alone.” How can you tell that even if a Sign be given them, they will indeed believe in it?(Surat al-An’am, 109)

Every man is destined to die on a certain day, which is decided in Allah’s sight. When that time comes, angels assigned by Allah descend on man to take his soul. If it is the death of a faithful person, then angels greet him, giving him the good news of Paradise and take his soul with ease. If it is the death of a disbeliever, on the other hand, then angels inform him that he will be exposed to a degrading torment. At that very moment, seeing what should have been obvious to them, those who disbelieve will submit themselves. However, after that point, nothing, not even having faith, will avail the disbeliever, for the time granted to him is already up. Allah conveyed this fact to those seeking excuses for their disbelief and commanded the Prophet Muhammad (saas) to address the people as follows:

Are they waiting for the angels to come to them or for your Lord Himself to come, or for one of your Lord's Signs to be given to them? On the day that one of your Lord's Signs does come, faith shall not avail the soul that had no faith or did not put its faith to good uses. Say: "Wait, then if you will; we too are waiting.”(Surat al-An’am, 158)