Oh, Roseanne, what have you done?

Well, sadly we all know, don't we? You sent out a tweet about a former aide to Barack Obama which was racist, derogatory and unpleasant. And now your show has been cancelled by ABC, even though it had been a massive hit.

Now let us all watch, listen and learn. Roseanne Barr's tweet is a walking, talking object lesson in the truth of what the New Testament says: 'Consider what a great forest is set on fire by a small spark. The tongue also is a fire, a world of evil among the parts of the body' (James 3:5-6).

In this particular case, that small spark of a tweet has set a fire which resulted in hundreds of people losing their jobs. All those little-known staff workers involved with Roseanne's hit show now suddenly find themselves without work. And, in turn, all their families are wondering how they will make ends meet. No wonder Roseanne has apologised to them all today. The spark, indeed, became a raging and consuming fire: and real people have been burnt.

No wonder James uses such a stark picture to speak of the power of words. No wonder, also, that as well as comparing the tongue to a fire, he likens it to a bit (the small piece of equipment put in a horse's mouth to direct the whole animal) and to the rudder of a ship – again something small with a big impact, in this case steering the course of the boat.

The more we think about words, the more we realise they are in fact the most powerful force in the universe. Not for nothing does Genesis portray God as 'speaking' the universe into existence. Not for nothing does the New Testament speak of Jesus as 'sustaining all things by his powerful word' (Hebrews 1:3).

Your words can be an immense power for good, or power for ill. There's an old saying which claims, 'sticks and stones may break my bones, but names can never hurt me'. But that's not true, is it? How we address others – our spouse, our children, our colleagues, the cashier, the bus driver, the cold-caller – can have a massive impact. Not for nothing do we speak of 'cutting remarks' because words can wound and cause lasting mental and emotional scars.

A former clergy colleague of mine once shared with me the simple acronym he tries to remember when speaking to people or writing something. It's 'THINK'. We have to ask ourselves, he said, are our words Truthful, Helpful, Intelligent, Necessary and Kind?

And this is a challenge for all of us. Yesterday after lunch at a particularly inconvenient time I had a phone call from someone trying to sell me a different broadband deal. I hadn't asked for the call, I wasn't interested in the offers, and I think I made that clear. But I did so in a way which had less of the graciousness in it than that to which I aspire.

So who will we speak to today? To whom will we send an email? What will we tweet about? What will we write about? What will our work colleagues take from our words? And our loved ones? And those we encounter in shops or as we go about some other form of leisure?

All this, needless to say, is a particular challenge for Christians. No wonder the Apostle Paul exhorts believers to 'let your speech always be gracious [and] seasoned with salt' (Colossians 4:6). He's talking within the context of knowing how to explain our faith, of course – but I can't believe he just wants us to turn on the graciousness in those situations while neglecting it the rest of the time!

Jesus, of course, was rather blunt in his language sometimes. He described some of the religious leaders of his time as 'like whitewashed tombs, which on the outside look beautiful, but inside are full of the bones of the dead and all kinds of filth,' (Matthew 23:287). But we need to remember he spoke with a unique divine authority – an authority which could see directly into the hearts of others and thus pronounce the authoritative judgement of God in a way that we, as his disciples, simply cannot. Some of the other blunt passages in the New Testament function in a similar way.

For most of us the problem is that we simply do not, as my friend advised, stop and THINK. The Book of Proverbs in the Old Testament reminds us: 'The mouths of fools are their undoing, and their lips are a snare to their very lives' (18:7). But, conversely, 'The tongue has the power of life and death, and those who love it will eat its fruit' (18:21).

Roseanne Barr's tweet is a lesson for us all. But then again, let's be honest, there but for the grace of God go any of us. Life and death: what will our words bring today to those who hear us?

David Baker is a former daily newspaper journalist now working as an Anglican minister in Sussex, England. Find him on Twitter @Baker_David_A