And this is the boldness we have in him, that if we ask anything according to his will, he hears us. And if we know that he hears us in whatever we ask, we know that we have obtained the requests made of him. If you see your brother or sister committing what is not a mortal sin, you will ask, and God will give life to such a one—to those whose sin is not mortal. There is sin that is mortal; I do not say that you should pray about that. All wrongdoing is sin, but there is sin that is not mortal. (1 John 5:14-17, NRSV)
Sin is any wrongdoing that separates us from God. There are sins that lead to death, mortal sins, and sins that do not lead to death. And if a sin is not mortal you can pray to God for help for those you see committing these sins. And that will give life to others.
So request that God give life to those you see that are separated from Him.
By praying for others you are also bringing life to yourself.