Established History Of Isa صلى الله عليه وسلم Being Crucified
Good answer Fahad. If Allah made them believe that Jesus was killed or they assumed it, whatever the case may be, we trust Quran and follow its guidance. We do not need to argue or convince anyone… I am not sure why we need to do that. Even Allah instructed prophets not to do this. Their job was just to deliver message. Only Allah can provide guidance whoever is deserving to be guided and whoever seeks his guidance.
Academically, the whole writing and compilation of Gospels can be questioned and Christiaity stands on a very thin ice if we were to approach this from an academic standpoint. Regarding Barnabas, I personally do not find it appealing to present Barnabas as an argument to non-muslims. However, Quran has already answered this Question with one fact-based statement and a second principle based statement. Fact-based statement being that matter was made “ dubious ” thus not denying their claim altogether, infact pointing towards the fact they it was made dubious in way which could have lead others to believe that Jesus (sws) was crucified and secondly, the principle stamement that Prophets (sws) (i.e. Rasuls) are under protection of God and God would never let munkireen touch a Prophet like this.
Since Bani-Israel were to be punished till the day of judgement (Qiyamah), it seems that they were given every opportunity to back out and revert back to the truth and also every chance till the end until they actually commited the crime from their end, so that no excuse would then be admissible as per requirements of Justice. That is why maybe the matter had to be made dubious for them to actually commit the crime.