Thanks for posting from God's word! There are so many things that can be said. One thing that strikes me about what is said here is to go and speak to a brother (or sister) who sins. It goes very strongly against my natural inclination to stick my nose in other people business or for them to bother me. But I think this assumes that you are part of a community of believers and then that we do have a responsibility to each other, to watch out for each other. Of course this must be done with great care, and an attitude of prayer and humility...