Substitute “Koran” for “Bible” and “Christians” for “irrational atheists” and see if you would agree with the statement.
Trying to argue your point by citing the Bible doesn’t work if the other person doesn’t agree with the Bible.
Heck we Christians have arguments over what the Bible means and we all believe in it!
The Bible is a good start because it is God’s Word inspired and written by the Holy Spirit. The Bible is what changes lives. So, yes, you should start with the Bible and pray for wisdom.
The Word of God is your sword. Don’t lay it down.