Asalaamu alaykum,
Wa alaikumu as-salam.
Many thanks for your sincere response, but the Quran is quite clear in regards to the ability of Jews and Christians to gain entrance into Paradise.
The Jews and Christians who followed the authentic teachings of their Prophets (pbut) will enter Paradise. However, if they were exposed to the Truth which Islam and rejected it and the Prophet Muhammad (pbuh), they will enter Hell. If they weren't exposed to the Truth (Islam), they will tested by God on the Day of Judgement. God will take a covenant from them and He will ask them to enter. Whoever enters Hell will find it safe and cool and will enter Paradise after that brief but tremendous trial. Those who don't enter will end up thrown in Hell.
Sure some may be misguided, in that they pay tribute to the creation rather than the creator, but we are all sinners, we are all misguided in some respect, no matter how hard we try. Modern day Christians do not join another "God" with Allah, rather they believe that there is only one God who manifests himself in various forms.
This is wholly incorrect.
They do blaspheme who say: "Allah is Christ the son of Mary." But said Christ: "O Children of israel! worship Allah, my Lord and your Lord." Whoever joins other gods with Allah,- Allah will forbid him the garden, and the Fire will be his abode. There will for the wrong-doers be no one to help. (5:72)
Like the verse says, those who say and believe that God is Jesus (pbuh) are in fact practicing Shirk which is a broader term and it doesn't mean solely "joining other gods".
Those who say that God manifests Himself in various forms, i.e. as Jesus (pbuh), are disbelievers. Those who say he is the Son of God and a Lord are disbelievers. No way around this.
They have taken as lords beside Allah their rabbis and their monks and the Messiah son of Mary, when they were bidden to worship only One Allah. There is no Allah save Him. Be He Glorified from all that they ascribe as partner (unto Him)! (9:31)
And they say: The Beneficent hath taken unto Himself a son.
Assuredly ye utter a disastrous thing
Whereby almost the heavens are torn, and the earth is split asunder and the mountains fall in ruins,
That ye ascribe unto the Beneficent a son,
When it is not meet for (the Majesty of) the Beneficent that He should choose a son.
There is none in the heavens and the earth but cometh unto the Beneficent as a slave. (19:88-93)
To firmly state that a Christian or a Jew is barred from Paradise for believe what he or she was taught as a child is wrong, it is a matter between that person and Allah.
Like I said, if such a person is exposed to Islam, he will be in Hell. If he wasn't exposed, he might still have a change like explained above.
I personally cannot believe that a person who truly dedicated their life to Allah, did good, and lived a righteous life would be absolutely barred from Paradise just because he or she chose to call themselves Jews or Christians. This is as if to say people like Mother Teresa, Gandhi, Rosa Parks, etc. are barred...
Well, we can't speak of the fate of specific people. But for the sake of arguement, let's say Islam was presented to these people and they rejected it, didn't accept it, then their end is Hell. It doesn't matter how much good they did if they rejected the Truth.
Those who deny Allah and His messengers, and (those who) wish to separate Allah from His messengers, saying: "We believe in some but reject others": And (those who) wish to take a course midway,-
They are in truth (equally) unbelievers; and we have prepared for unbelievers a humiliating punishment.
To those who believe in Allah and His messengers and make no distinction between any of the messengers, we shall soon give their (due) rewards: for Allah is Oft-forgiving, Most Merciful. (4:150-152)