“keep a good conscience so that in the thing in which you are slandered, those who revile your good behavior in Christ will be put to shame.”

“but sanctify Christ as Lord in your hearts, always being ready to make a defense to everyone who asks you to give an account for the hope that is in you, yet with gentleness and reverence; and keep a good conscience so that in the thing in which you are slandered, those who revile your good behavior in Christ will be put to shame.”
1 Peter 3:15‭-‬16 NASB

http://bible.com/100/1pe.3.15-16.NASB