The person who honestly is searching for the truth based on objectivity and would have investigated Islam based on objectivity and honesty, would already have known that. Every person who has honestly searched about the whole story of Banu Qurayza would not bring this even up as they have heard the whole story and seen that nothing is left but to indeed agree on it. What you are doing is try to show somebody something, but that individual doesn't want to open his eyes to look at what you are trying to show him. So my question to you, how can you point at something so somebody can see it, if he or she doesn't want to open their eyes to look at? If you would even describe it in words, that individual would say...what are you talking about..all i see is darkness (inside of his eyelids). Which indeed he IS RIGHT, as all he sees is the inside of his eyelids which is darkness.
I have had discussion with many people of different philosophies even people who call themselves Muslims, but all they show is nationalism. When you corner them with some questions that they can't answer, because that shows their dishonesty to themselves and to others who are following the discussion. They just shut and won't respond anymore.
I have had a discussion with a guy who said he was a Jew. Based on our discussion, all he did was have blind faith in something, like Christians blindly follow the concept of Jesus(as) dying for their sins. Every time i gave him a question that he couldn't answer..he would not reply or say..every religion has it's "errors"=_=!. When i gave him the argument that cornered him so much, he never responded again. Sub'han'Allah, that really made me speechless of how Allah(swt) talks about these dishonest people and the ingredients to guidance. I mean if you are so dishonest and you KNOW that you are wrong, how come you don't admit it?..all pride and arrogance. Thinking if you admit that you are wrong is sign of "weakness"=_=! while it is a sign of wisdom as you would gain more knowledge from the other person who is right.
Then you have people who are confused why Allah(swt) says he guides whom He wants to guide. I have observed MANY different people and especially tried to look at minor details in searching for the dishonesty. SUB'HAN'ALLAH..i was shocked by what i discovered. I have seen people who are weak in imaan do sins, but are very honest in their actions and do truly believe in a Creator. They admit in everything. I have also seen people who are not Muslims and having almost all the traits a Muslim should have minus the praying, fasting etc. but do have good character etc. The minor details when you observe their behavior show their dishonesty. When you corner them with the obvious argument, instead of them pondering about your argument, they try to hop on another subject of trying to debunk Islam. When you corner them also on that, after a while..they just get all agitated and show signs that they want to stop the discussion. Those people i leave them be, as they themselves are the cause of not being guided by Allah(swt).
Sadly when we have discussions online it is hard to directly reveal the dishonesty of the person you are having the discussion with. However, i would suggest to think of such question that corner people instantly. This saves you A LOT of time. Time that you could rather have spend on something that YOU would even benefited from. Da'wah is a good thing, but it is a waist of time when you try to discuss with a person who is not being honest in the first place.
