Morality is possible even without the belief in divine existence and intervention. The following are the possible sources in which morality can come from, with giving some personal examples as well as an atheist myself:
1. Egoism: Doing things out of self interest, isn’t necessarily an immoral thing, if the deeds themselves can be beneficial for the self, for others or both. It is only natural for us to put ourselves in a top priority, because unlike babies, we as grownups need to learn how to take care of ourselves without the help of others. Preparing a meal and eating it by yourself, is an example that proves there is no necessary connection between self-interest and immorality, and is also proof that egoism is important our independence as mature people. I myself help random people I encounter when they request it, because seeing others being benefited, also makes me feel good, making my interest in helping others based on good feelings instead of bad ones.
2. Harmony: A good sense of harmony between people is imperative for optimal cooperation and safety, and evil is unnecessary. Those who claim that good cannot exist without evil and evil cannot exist without good - how would you explain pure deeds of good and pure deeds of bad? Last time I helped someone was in a supermarket. She was to short to reach some product, so I reached it myself and handed it to her. Now explain to me what evil existed in this deed. If I were to refuse her request to help me, she would probably be angry with me or say bad things about me as I pass by. Why would I want others to be told bad things about me, let alone in my presence? The same goes in work, where I do even small deeds, such as lift boxes to tables of secretaries who are to weak to do it on their own. The fact that my contribution to others create a good sense of harmony, is sometimes sufficient for me to commit altruistic deeds.
3. Productivity: For me, productivity is a prime priority, because the products that are being created are a reflection and a representation of our inner merits. This is why I like working and even writing answers on Quora; I like to produce things, especially when it comes to writing. The morality behind it is that my products can benefit others and even help them on the philosophical and practical levels. Being in constant action at times makes me feel good about myself and worthy. This is why I sometimes wake up early in the morning on a free day and drink coffee, just to write, instead of potentially sleeping more.
4. Karma: While I don’t believe in an energy called “karma”, I do believe in the wisdom behind it: if I shall help others, it would be more likely they would help me in return, and if I will do bad things to others, they might to the same to me in the future. As I said before, evil is not necessary, and thus I do as best as I can to be in good relations with everyone I interact with.
5. The Law: Usually the law is what enables us to function in life with a possibility of optimal sense of safety. Think of what your countries did to you: gave you different services, provided you or your family with employment, protected you from criminals and terrorists, granted you civil rights, and so forth - when I am to see a suspicious activity (something that seldomly happens), I usually called the police. The latest example was a few years ago, when I saw a girl being beaten by another girl in the middle of a park. Everyone watched and most did nothing, with few people trying to reach her physically, only to be blocked by the beating girl’s goons. There were even people watching this scenario from the safety of their homes. I am unsure if anyone else called the police but me. I did that because I know the law is there to protect me and others from possible dangers, and thus I thought to myself “why should I step away if I can call the police if the police’s purpose is to protect and serve us, the citizenry?”
We can thus conclude from all of this is that atheists can be act good as well, and that religion does not have to be the only source of morality. Let us not advocate the negative stereotypes and generalizations that are usually associated with atheists and atheism.