Here is a portion from Calvin’s sermon on Acts 5:13-16
We are shown our responsibility. Once our Lord has brought us to the knowledge of salvation, we must so glorify him in our lives that people will realize we have not received the teaching in vain. That is why God’s teaching must not be preached in vain among us and why we must not, by our dissolute lives, give occasion to the wicked to say, as has been their custom, “Well it is true those people confess the gospel, but they do not know what that means, or at least they do not act like they do.”
That is why we are told our good life and behavior are to serve as an affirmation that the teaching of the gospel is good and holy and the way to life and salvation. It is not that God needs us to confirm his teaching, but it pleases him to use our holy and upright way of life to confirm the teaching in the eyes of men. That, I say, is what Luke admonishes us to do. So, if we profess the gospel, our lives must simultaneously correspond to it and reflect such holiness that the pitiable people who do not know the gospel may have the opportunity to think and say, “What is going on here? People say this teaching is false and a lie and considered heresy, but the fact is it has great power because those who have been instructed in it are completely changed. And we know it is a very difficult thing for a man to be made new. So, no matter what people say, that comes from God.” This, then, as I have said, is why we should direct all our effort toward living upright lives: so that unbelievers themselves might be constrained to glorify God.