Jnana, bhakti, yoga and karma - these are the four paths which lead to spiritual freedom. One must follow the path for which one is best suited. But in this age, special stress should be laid on karma yoga.
The way of presentation is different according to each religion. In theistic religions like Buddhism, Buddhist values are incorporated. In nontheistic religions, like some types of ancient Indian thought, the law of karma applies. If you do something good, you get a good result. Now, what we need is a way to educate nonbelievers. These nonbelievers may be critical of all religions, but they should be decent at heart.