In a very real way, we are blameless before God because of Christ’s work on the cross and our faith in his death on our behalf. But in a day to day practical way, “blamelessness is a verdict reached by those who observe a life and compare it to a standard. Such a person or group has credibility, the first essential for effective evangelism. We must be good news before we share it.” (Joe Aldrich, Lifestyle Evangelism)
Of course the standard we live by must be worthy of the God we serve, but when it is, we become, as Joe Aldrich says so well, good news.
We’re not blameless though in our daily lives; at least I’m not. And we shouldn’t try and make people think we’re something we aren’t. They’ll know anyway and then they can add hypocrite to our other failures.