It is not easy being a follower of Jesus. He himself reminds us we are like sheep trying to live amidst wolves. Jesus elsewhere tells us we will be persecuted, opposed, misunderstood. While we live in a world with many pleasures, and many opportunities to do good, that same world is resistant to the rule of Jesus.
We can react to this by going to extremes. One extreme is to assume battle stations every moment of every day. Enemies are everywhere; paranoia reigns. Conspiracies are seen where no such conspiracies exist. And so we can fight fire with fire, and end up being seen as angry, aggressive crusaders for our cause.
Or we can just roll over and become like tame puppies, inviting the world to pat us and stroke us. We assure that world we are no threat, that we are really just like them only a bit on the religious side. We assure them that any Christian belief they find offensive is really a misunderstanding and we mean to cause no offence whatsoever.
Jesus is trying to strike a balance. We are to be aware of those who oppose us, not at all naïve or gullible. Not at all timid pushovers. And yet we are not to deliberately go out to stir up trouble and pick fights. In other words, be serpents and doves.