Jesus said, "You are the salt of the earth" and "You are the light of the world".

We know the sayings very well – they're in Matthew 5:13-16. And perhaps we've thought about what they mean. Christians are meant to make a difference in the world. We're to stand up for what's right, we're to campaign for justice and righteousness, and we're to speak truth to power. It's about being prophetic voices in a world that doesn't acknowledge God; if we're called to be the light, it's because there's so much darkness all around.

That may all be true. But perhaps we should go a bit further back. Why did Jesus, or why did Matthew, put these sayings here? Why immediately after the beatitudes in the first few verses of Matthew, the 'blessed ares' – "Blessed are the poor in spirit, the mourners, the merciful, the pure in heart?"

A text without a context is a pretext. So what this seems to be saying is that the people who are the salt of the earth and the light of the world are the same as those who hunger and thirst after righteousness, who are peacemakers and who are persecuted.

Being salt and light means being this kind of person. It's not so much about what you do; it's much more about what you are. It's about your character, and you are in your inner being. When you go home and you close the door and you look in the mirror, who do you see looking back? That's the person who's called to be the salt of the earth and the light of the world. Another way of thinking about the beatitudes is that they're 'beautiful attitudes'. Is that person looking back at you pure in heart, merciful, a peacemaker?

That's who Christians are called to be. That sort of person is attractive to others because they look like Jesus. Oliver Wendell Holmes, the American judge and writer, once said: "I might have entered the ministry if certain clergymen I knew had not looked and acted so much like undertakers." The English poet, AC Swinburne, was reflecting on the victory of Christianity over paganism in the ancient world. He wrote: "Thou hast conquered, O pale Galilean/ The world has grown grey from thy breath." But Christians who are salt and light aren't gloomy and grey. They are the most alive people of all.

We can't change our characters. Some of us are quiet, some of us are noisy. Some of us are the gregarious type, fond of parties, while others like a bit of peace. But whatever sort of person we are, we aren't miserable, or negative, or cynical. The 'beautiful attitudes' are attractive because they are Christ-like. They mean we reach out to other people with his love and mercy. The flavour we add to the world is meekness and mercy. The light we shine is peace and purity.

If we really want to be the salt of the earth and the light of the world, we need to learn the character of Jesus.

Follow Mark Woods on Twitter: @RevMarkWoods