1 Pet 3:15     But in your hearts set apart Christ as Lord. Always be prepared to give an answer to everyone who asks you to give the reason for the hope that you have. But do this with gentleness and respect

      

There is quite a challenge in today's verse but it only really becomes clear when you see the verse in context. Peter has just said, “Who is going to harm you if you are eager to do good? But even if you should suffer for what is right, you are blessed. "Do not fear their threats; do not be frightened.” (v.3,4) It is really all about standing up under opposition which was a very real part of the life of the church when Peter was writing.

So negatively he's just said, don't be put off by their opposition. Now in today's verse, he basically says, determine to hold Christ as Lord and remain faithful to him and true to him. He then goes on, in the way you do this, always be ready so you know what to say by way of explanation when you are questioned.  In other words, if people come against you for being a Christian, be ready to explain simply and with respect why you are a Christian. Know what you believe and why you believe. Bring a rational answer to them when they question you.

Now this means that we should think about these things and think about how we can explain our faith because, who knows, our explanation might be the cause of helping someone opposing us to come to know the Lord. If we can give a reasonable answer, they may not agree with it on principle, but it may leave them thinking and if they are honest, they may come to agree with what you say.

To expand on this, this may not only apply to answering those in opposition to us, it may also apply to those who simply want to know what the Christian faith is all about. The same still applies, be gentle and gracious, not arrogant in your reply, and have a thought out testimony of your own experience, and a thought out understanding what the Gospel is about.