One cannot argue with an atheist and be an effective witness for Christ. If you really want to spread the Gospel, it's easy. There are people all around you that are hungry for meaning. There are poor people around you who need a job, clothing, food, sympathy, etc. There are people in prison who got there (the first time, not hardened criminals) because they are poor, uneducated, lack skills, and you can witness to these folks by sincerely taking them under your wing and helping them when they get out.
Why not spend more time helping those people, and less time trying to cite chaper and verse of the Bible to people who don't believe it?
Example: I'm a hard-core conservative Christian (Christ-follower if that word bothers you). If someone cited chapter and verse from the Quran, would it persuade me? Heck no. It would be a waste of their time and mine.
A lot of atheists are very intelligent scientifically and artistically minded people. They tend to have a deep appreciation for Nature and Culture. If you're sincere, why not befriend one and in making a friendship over time if there's a good moment, then share your faith? That's the traditional way to bring people to Jesus or at least sincerely share your faith.
Getting in their face and chest-thumping might make you feel better, but I'll bet it makes you feel worse too. In the heat of an exchange, you say things, often sinful things because you lose your temper.
If you were to argue every day with people on GLP about Jesus, realistically how many people do you think will actually become Christians by beating them over the head with the Bible? Probably zero. So you wasted your time, talent, and treasure like the servant who buried it in the soil, didn't you?
Believe me, there are definitely times I see purported Christians who actually are teaching from Gnostic texts and so are dangerously perverting the Gospel. Rather than spend all my time arguing with them, there's Free Will, a law from God, and so it's up to them to believe in the Bible and Jesus. I likely will not convince them. They have to decide to believe in that.
Therefore it's better for me to spend my time on GLP doing other passions like prepping in my case and showing people how to prepare for a real disaster. See my 1st link in my sig for that.
The world is a beautiful place spoiled by discord and most of that is caused by humanity. By working together on other issues, we can understand each other and find some common ground in most people. Then and only then, friend to friend or acquaintence to acquaitence, can witnessing happen.
Stop arguing, and start friendships and witnessing, if the goal is to spread the Good News about Jesus.
Honestly, why not talk to your friends and say, "My church is having a dinner. We really love your company and we like the things our church is doing to help the poor. They are so sincere there. The music program is spectacular. The youth ministry is quite well known. Can you visit with us this Sunday? Please do, because you have so many talents and could bring your skills to our church and make it stronger. Come sit with us in church. We'll drive with you so you don't get lost."
This method^ above has a success rate of over 50%. That's a much better way to witness.