The Old Testament (OT) vs. the New Testament (NT) is just that, history vs. now.
Following the teachings of Christ is NOT what the Crusaders did. They were the EyeForAnEye Gang...stupid from the word go.
As for Islam and the drivel coming from Muhammed...poison from the trampled. Islam is like anything against another religion...hell (pardon the pun), they can't even get along with their own kind...how would ANYONE (Muslim, Jew, Christian, Spahgetti-Monster, Buddist, Moaist, Atheist, whatever) expect anyone to be of the same mind and matter?
The NT is what God wanted everyone to be like...Christ-like in that you treat everyone as you would like to be treated, believe in one God, not some flavor-of-the-day nutjob that eats grass and drinks his urine.
Just believe. No prayers to some crumbling wall, shiney temple, bullet-scarred mosque, dirt hut, church down the street or some piece of cloth hanging in some wad's closet. No sacred cow, bull, beetle, cat or cat's scat. No marking yourself as to what sect you belong to or section-housing you escaped from. No tithing, alms or donations to some project to be built, donated to, covered up or to cover underfunding from some snake-oil hack's sale.
Just believe that Christ died as the One and Final Offering...the lamb for God.
So simple to do yet so hard for many to understand and accept.
Does anyone need to know you did it?
Nope.
It's between you and God.
Now...if you'd like to talk to others about it...don't put on the armor, get on a high horse and take on the masses.
Just ask if anyone's interested.
Those that don't mind listening, will listen.
The others?
I believe the saying that best applies to this thread is this "Do not give what is holy to dogs, and do not throw pearls before swine, lest they trample them under their feet, and turn and tear you to pieces." (Matthew 7:6).
We know a few on here who have been torn to pieces.
But, can we fervently hope that those that might be perceived as dogs and swine come about and have a change of heart? Nor should they be expected to have to openly profess their change. Remember, it's a process that need only be between themselves and God.
It will and should, eventually, become evident on its own, by their words and deeds.
BTW, Hell is real. We only THINK we know what it's about. None of us will understand, truly, the true horrors of its existence until it's too late.