I agree with looking up to heaven, but if people are not asking you for this information, it only turns them off to God to hear it from you. Condemning people is not the way to move people to love God. Show God's love, and peace, and then people who genuinely want to know God will come and ask you about Him. That's when and how you share God's message. I know you are trying to do good, but you are actually not by presenting your message in this way. When you preach a sermon based on Scripture in Church, it's to an audience that has come to learn about God. Here it is to an audience that hates God. If a Moslem came up to you and said that unless you beleive in Mohammed, you will not get into heaven, because Mohammed said so, would you accept that? I don't think so. No atheist is going to accept what you say as a Christian just because you say it. Even if you're right, you're not convincing, and the way you do present your message, as mentioned, is exactly what turns a lot of people away from God. Now you have to answer for that. Be smart about it.