"All of them - as they surrender unto Me - I reward accordingly. Everyone follows My path in all respects, O son of Pritha." (Lord Krishna, Bhagavad-gita, 4.11)
As Shri Krishna says in the Bhagavad-gita, everyone follows Him in all respects. The all-attractive one has something that appeals to every kind of person. As such there is actually no such thing as an atheist. To those who know the spiritual science in truth the term has a different meaning.
This is the back side of God. Think sinful behavior. Think doing things the wrong way. You purchase a new piece of furniture. There is a proper way to assemble it. Since there is freedom of action for a living being, there are also countless wrong ways to put the item together.
The wrong way is adharma. The material world is like a shadow or reflection of an eternally existing realm that is free of anxieties, Vaikuntha. There is no inebriety in the spiritual world, but in the material world there is illusion at every corner.
The living being tries desperately to take that which is impermanent and make it permanent. The triumph in work, school, or sports turns into a distant memory after a few short years. Revisiting that time through photo or video technology may bring some temporary delight, but then the sad reality kicks in. Time has changed everything. Time has guaranteed that there will never be a return to that period of glory.
Adharma is the way of the atheist. They see God, but only His back portion. This means that just the separated, external energy is worshiped. Even if there is a stubborn resistance to worshiping any acknowledged higher authority, eventually there is submission to time in its most ghastly form: death. In this way even the atheists see God and bow down to Him.
This is religiosity. Righteousness. Doing things properly. Following the way of authority, as passed down through a chain of teachers, each dedicated to the same purpose: returning others to Vaikuntha. Dharma cannot be concocted. It cannot be altered. It may be more refined or specific depending on the circumstances and the desired goal, but at the root level it is the same for every living thing.
That is because dharma is what defines an object. For the essence of life, the spirit soul, dharma is service to the Divine. Following dharma equates to theism, or belief in God. The more a person stays on this side of the Divine, the more they enjoy through His association.
That is the real difference between real religion and aimless sense gratification. Those in the dark, seeing only the back side of God, enjoy very little. They get whatever the shadow world, the material energy, has to offer.
Those seeing the front side receive everything the personality Himself has to offer. He turns time upside down, into an auspicious factor, allowing for renewed opportunities in service, which is what makes the soul happiest. God shows His different transcendental forms, which are beautiful and purifying. One look at Bhagavan, the person who holds all fortunes, in the proper mood can change the consciousness forever. Then no longer will the back side of the material energy be an option for association. Only Vaikuntha, whose conditions can be replicated even in the material world, will be the place to live.
Argument with atheist to expect,
But following Krishna in all respects.
Just looking at side the back,
Personal association to lack.
Little happiness with misery bound,
True joy on other side found.
Delightful, all-attractive vision getting,
And so no more in illusion setting.