@LukeAlmighty i'm a Christian (as in follower of Christ) but i hate religion so islam. i'd rather get rid of catholicism than atheism. as a disclaimer, though, i know i don't have quite the same views as a lot of other Christians do about some things so i wouldn't necessarily extrapolate what i'm about to say to all Christians.

it is a little hard for me to put succinctly, but by large i consider an atheist who does good things to still be working in service of the Lord. on the flip side, a religious person doing bad things is no longer in the service of the Lord. you don't just get to say you're a good person because you're religious. i see religion, generally speaking, to not be in service of the Lord because they are complicit in and complacent towards evil and corruption. an atheist might do something bad due to their lack of belief, but a religious person might do something bad or let something slide BECAUSE of their belief. i think the latter is scarier when you think about what that means on the grand scale.

Matthew 7:16-23
"Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles? Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit. A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit. Every tree that bringeth not forth good fruit is hewn down, and cast into the fire. Wherefore by their fruits ye shall know them. Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven. Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works? And then will I profess unto them, I never knew you: depart from me, ye that work iniquity."

in my interpretation, it matters more that you are aligned with "good" (however nebulous that may be) than "religion." a man who is good but does not know Jesus is better than a man who is evil and claims to know Jesus, and Jesus confirms they are worse off for it. what someone does and how someone acts is far more important than what they believe in, or say they believe in.

all of Matthew 23 is really good for this too, in fact it is my favorite chapter in the Bible because it's Jesus absolutely dunking on religious hypocrites, telling them they won't make it to heaven and that they are more or less hellspawn. i bring that up to say that i really don't think it is whether or not you believe in God that matters, it is what you do in this life and the content of your character that does.

i know a lot of Christians tend to think that as long as you know Jesus you are saved, and if you don't then you aren't. that just doesn't seem right to me, though. i don't think going to church and saying your prayers and trying to spread the "good word" is nearly as important as being a genuinely good human being, especially if you're a despicable person behind that veneer of righteousness.