Praise be to Allah.
This idea is not correct at all. From the time that Islam emerged, with the mission of the Seal of the Prophets, our Prophet Muhammad ibn ‘Abd-Allaah ibn ‘Abd al-Muttalib al-Qurashi al-Haashimi, a Messenger to all of mankind and the jinn, all other paths to Paradise were shut off, apart from his path, (peace and blessings of Allaah be upon him). Whoever dies calling on any god besides Allaah, whether it is an idol, an angel who is close to Allaah, a Prophet who was sent, a rock, a tree, a grave, a jinn, a tomb of a “saint”, or any of the members of the Prophet’s household (“Ahl al-Bayt”), or anyone else, no matter who it is – if proof (of his misguidance) is established but he still persists, he will be one of the people of Hell, there to dwell for eternity without end; he will never enter Paradise at all.
There are the texts of the Qur’aan and Sunnah which explain this matter; these texts and reports are mutawaatir [i.e., narrated by so many people from so many people that it is inconceivable that such a great number of people could all have agreed upon a lie]. Allaah tells us that He will not accept any religion from anybody except the religion of Islam with which He sent Muhammad (peace and blessings of Allaah be upon him). Allaah says (interpretation of the meaning):
“And whoever seeks a religion other than Islam, it will never be accepted of him, and in the Hereafter he will be one of the losers.” [Aal ‘Imraan 3:85]
“This day, I have perfected your religion for you, completed My Favour upon you, and have chosen for you Islam as your religion” [al-Maa’idah 5:3]
“Verily, Allaah forgives not that partners should be set up with Him (in worship), but He forgives except that (anything else) to whom He wills; and whoever sets up partners with Allaah in worship, he has indeed invented a tremendous sin” [al-Nisaa’ 4:48]
“Verily, Allaah forgives not (the sin of) setting up partners (in worship) with Him, but He forgives whom He wills, sins other than that, and whoever sets up partners in worship with Allaah, has indeed strayed far away” [al-Nisaa’ 4:116]
The Prophet (peace and blessings of Allaah be upon him) said: “By the One in Whose hand is my soul, no Jew or Christian will hear of me then not believe in that with which I have been sent, but he will be one of the people of the Fire.”
Allaah has warned the Kuffaar of an eternity in Hell in a number of aayaat in His Book. In Soorat al-Nisaa’ He said (interpretation of the meaning):
“Verily, those who disbelieve and did wrong; Allaah will not forgive them, nor will He guide them to any way Except the way of Hell, to dwell therein forever; and this is ever easy for Allaah” [al-Nisaa’ 4:168-169].
And Allaah says in Soorat al-Ahzaab (interpretation of the meaning):
“Verily, Allaah has cursed the disbelievers, and has prepared for them a flaming Fire (Hell). Wherein they will abide for ever” [al-Ahzaab 33:64-65]
And Allaah says in Soorat al-Jinn (interpretation of the meaning):
“and whosoever disobeys Allaah and His Messenger, then verily, for him is the fire of Hell, he shall dwell therein forever” [al-Jinn 72:23]
And Allaah says, describing the state of the mushrikeen in Hell (interpretation of the meaning):
“Verily, whosoever sets up partners (in worship) with Allaah, then Allaah has forbidden Paradise to him, and the Fire will be his abode. And for the Zaalimoon (polytheists and wrongdoers) there are no helpers” [al-Maa’idah 5:72]
And Allaah sent His Messengers and revealed His Books with only one message: that there is only One God (Tawheed) and that mankind should worship Him Alone, with no partner or associate. This is obligatory on man: to believe in this in word and thought and deed, for He is the Only One Who is deserving of worship. This is what is referred to in the aayah (interpretation of the meaning):
“That is because Allaah, He is the Truth, and that which they invoke besides Him is Al-Baatil (falsehood, Satan and all other false deities)” [Liqmaan 31:30].
The aayaat of the Qur’aan repeat and reinforce this message, for example (interpretation of the meanings):
“Worship Allaah and join none with Him (in worship)” [al-Nisaa’ 4:36]
“And they were commanded not, but that they should worship Allaah, and worship none but Him Alone (abstaining from ascribing partners to Him)” [al-Bayyinah 98:5]
“Say (O Muhammad): ‘I am only a man like you. It has been revealed to me that your Ilaah (God) is One Ilaah (God ¾ i.e. Allaah). So whoever hopes for the Meeting with his Lord, let him work righteousness and associate none as a partner in the worship of his Lord.’” [al-Kahf 18:110]
The Messengers all brought the same Message, repeating this call. Allaah says (interpretation of the meaning):
“And We did not send any Messenger before you (O Muhammad) but We revealed to him (saying): Laa ilaaha illa Ana [none has the right to be worshipped but I (Allaah)], so worship Me (Alone and none else).” (al-Anbiyaa’ 21:25]
Hence the Kufr of the Arabs intensified when the Prophet (peace and blessings of Allaah be upon him) came to them calling them to believe in Allaah Alone and worship Him Alone, and to give up and abandon all false gods, intercessors and partners, and to reject all of them. Allaah tells us about them (interpretation of the meaning):
“Truly, when it was said to them: ‘Laa ilaaha illAllaah (none has the right to be worshipped but Allaah),’ they puffed themselves up with pride (i.e. denied it). And (they) said: ‘Are we going to abandon our aalihah (gods) for the sake of a mad poet?’ Nay! he (Muhammad) has come with the truth and he confirms the Messengers.” [al-Saaffaat 37:35-37].
Allaah tells us that everyone who worships or calls upon any other god apart from Allaah will be gathered together with him in the Fire of Hell, as He says (interpretation of the meaning):
“Certainly you (disbelievers) and that which you are worshipping now besides Allaah, are (but) fuel for Hell! (Surely) you will enter it. Had these (idols) been aalihah (gods), they would not have entered there (Hell), and all of them will abide therein. Therein they will be breathing out with deep sighs and roaring and therein they will hear not.” [al-Anbiyaa’ 21:98-100]
To sum up, the person who dies after reaching the age of puberty and is a mushrik who disbelieves in Allaah and calls upon another god apart from Allaah and believes that these other gods can benefit or harm him, or that they have any power at all, is a kaafir and is one of the people of Hell who will dwell therein for eternity, whether he was under or over the age of 40. What counts in Islam is reaching the age of puberty, nothing else. Puberty is reached when one of three signs occurs in males, to which a fourth sign is added in the case of females. These three signs are as follows:
Reaching the age of fifteen years.
Growth of hair in the pubic area (private parts) – for both men and women.
Emission of maniy [sexual fluid] accompanied by feelings of desire, whether in a wet dream, during intercourse or through any other means.
In the case of women there is a fourth sign, which is the onset of menstrual bleeding.
If any of these signs appear, the person is judged to have reached puberty, so he becomes a responsible adult, required to obey all commandments and heed all prohibitions. This does not mean that a child or a person who has not reached puberty is permitted to associate others in worship with Allaah or to call upon anyone other than Him. If he does that, he is counted as a kaafir, but if he dies in kufr before reaching the age of puberty, then his case rests with Allaah in the Hereafter.
If a person is good or humble or generous or respectful towards his parents or any other worthy characteristic, this will not help him at all with Allaah; he will get his reward in this world. ‘Aa’ishah (may Allaah be pleased with her) reported that she asked the Prophet (peace and blessings of Allaah be upon him): “O Messenger of Allaah, during the Jaahiliyyah, ‘Abd-Allaah ibn Jad’aan used to uphold the ties of kinship, set captives free and honour his guests (and she mentioned a number of good characteristics, but he was a mushrik and died as such). Will that be of any benefit to him?” The Prophet (peace and blessings of Allaah be upon him) said: “No, for he never said, ‘O Lord forgive me my sins on the Day of Reckoning” – meaning that he was a kaafir who did not believe in the resurrection and reckoning, so the good deeds he used to do will not benefit him. A similar example is Haatim al-Tayy; the Prophet (peace and blessings of Allaah be upon him) told his daughter Sufaanah, “If your father had been a Muslim we would have prayed for mercy for him.”
And Allaah knows best.