I Peter 2:15 It is God's will that your good lives should silence those who make foolish accusations against you.
God wants you to live in such a way that your life will shut up those who would accuse you of wrong or hypocrisy. When we don't live the way He wants us to, we are out of God's will for our lives. God will not bless those who are not living honorable lives before Him.
How we live affects our witness, whether we want to admit it or not. When we don't practice what we preach, we are giving others ammunition to use against the body of Christ and even Christ himself. People want to know what works in real life, not theories about what works. There are all kinds of theories out there about how life should be lived and if we don't show the world how life in Christ works, we do more harm than good.
People can come up with all kinds of arguments against what we believe, but they can't argue against what works. When we live godly lives it silences those who oppose it. They may not embrace it for themselves, but they can't refute godliness as it is lived out.
Are you living God's will for you? Are you living in such a way that no one can question whether or not your professed faith is real or not? You cannot live a godly life until you let Jesus be your Lord as well as your Savior. Only those who are fully surrendered to Christ will do God's will for them.