The Bible says that if we are saved then we will show good works. So what are good works? Is it not sinning, or is it helping an old lady across the road? And if it is helping an old lady across the road well, I’m going to say that unsaved people do that!!
The only “work” that God requires of us is to believe in the One He sent, Jesus (John 6:28-29). But that belief can produce changes in our behavior, too. We can become more conscious of our sinfulness and often perform more acts of kindness toward others than we did before.
Of course many unbelievers are also kind to others. The difference is believers usually do this out of gratitude to the Lord for saving them, but an unbeliever’s kindness will be motivated differently, perhaps out of a need to be liked, or to feel good about themselves. So while both may do the same thing, the motives that prompt them are different. We want to please the Lord. Unbelievers want to please themselves.
This is why the Lord said not to judge anyone, but to leave that up to Him because He’s the only one who can judge us on the basis of our motives. 1 Cor. 4:5 says He will bring to light what is hidden darkness and expose the motives of men’s hearts. He also encouraged us to perform our acts of kindness in secret because He knows how good it makes us feel to us to receive credit from others for what we do, even though it’s only temporary. He said those things we do in secret are the ones our father in Heaven will reward us for (Matt. 6:3-4) and His rewards last forever.