Conclusion

When people inquire about their religion, most people say that they are Muslims. However, many of them have not read the Qur'an, the just Book of Islam, even once. However, as has been mentioned throughout this book, the Qur'an is the revelation of Allah through which He introduces Himself and explains the real purpose of our life of this world and the next, as well as the attributes of moral perfection.

Leading a life unaware of Allah's expectations and being satisfied with fabricated religions is not befitting to a person's conscience and wisdom. Allah states that He sent down the Qur'an for people to read:

We have sent it (the Qur'an)down with truth, and with truth it has come down. We only sent you (O Muhammad) to bring good news and to give warning. We have divided up the Qur'an so that you can recite it to humanity at intervals, and We have sent it down little by little. (Surat al-Isra': 105-106) 

The Qur'an is unique, and therefore far superior to any other book. For this reason, the information that it contains is far superior to any other information. Every person who reads it with a sincere intention and sees the miracles, unique wisdom, and superiority that its verses convey will be guided to the truth. Whether people believe in it or not, the Qur'an is a reminder to all the worlds and is a miracle of our Lord, as we read in:

Say: "Believe in it or do not believe in it." Certainly, when it is recited to them, those who were given knowledge before it fall on their faces in prostration, saying: "Glory be to our Lord! The promise of our Lord is truly fulfilled!" Weeping, they fall to the ground in prostration, and it (the Qur'an) increases them in humility. (Surat al-Isra': 107-109) 

A person is never too old to read the Qur'an, understand it, and implement its commands in his or her life. This being the case, a person must not be seized by Satan's whispered incitements, such as: "You have not done it until today, so will it be of any use if you do it from now on?" and be cautious about similar satanic advice. Allah will hold people responsible for their most recent state. If a person, seeing the truth, turns to Allah and the Qur'an and starts to lead a life seeking His good pleasure, Mercy, and Paradise, Allah will accept his or her repentance.

Thus, those who know that they will die one day and live an eternal life, and who are aware of Paradise and Hell, must consider their situation by conscience and wisdom and then decide how to conduct themselves. What befits one's conscience and wisdom is to lead one's life by seeking Allah's good pleasure, His Mercy and Paradise, and to comply with His commands. As He states in the Qur'an:

Recite what has been revealed to you of your Lord's Book. No one can change His Words. You will never find any safe haven apart from Him. (Surat al-Kahf: 27)