Does anyone here know how to defend Christianity?

Today I got into a argument with a antitheist or reddit who said God started the flood and told people to rape each other. And I responded "that's not how God is" and that I have a relationship with God. One of them said "no you fucking don't" as if they knew me personally. And this was all on a post on how a Muslim became a christian brother in Christ, and the satanists in in the comments trying to make it their moment and berate our beliefs. Does anyone know apologetics here, and how I can defend myself ithis situation? Thanks!