Titus 3:2 & 1 Peter 3:15 

Titus 3:2

to speak evil of no one, to avoid quarreling, to be gentle, and to show perfect courtesy toward all people.  

1 Peter 3:15 

 but in your hearts honor Christ the Lord as holy, always being prepared to make a defense to anyone who asks you for a reason for the hope that is in you; yet do it with gentleness and respect,