Recently a man came up to me while I was out shopping and asked if I could spare him any money for a cup of coffee.

My first reaction, to be honest, was one of suspicion: was his request going to morph into a long sob story about having to travel hundreds of miles urgently by train for some mysterious family reason? Would this then involve him demanding a rather larger sum? Such things have happened previously. But on this occasion it didn't. So I responded in my usual way: I didn't give him any cash but went to the nearest coffee shop, bought a large cappuccino and took it back to him. He gratefully accepted it.

'Are you OK?' I asked. 'Have you got somewhere to live alright?' He replied: 'Oh yes, that's fine.' But he added: 'You know, times are hard.' And as he said these words he looked at me with such infinite sadness I could have wept.

We might think that anyone, anywhere, would help a fellow human in this way, whether with a simple cup of coffee or something similar. But it's not so. As The Times reported this week, photos from Shanghai showed a lady who had collapsed on a zebra crossing being ignored by passers-by. 'Many Chinese remain reluctant to do the right thing,' the journalist wrote. Indeed as long as 80 years ago, one author there noted people's reluctance to help others, he added.

The teaching of Jesus about love makes a transformative difference, both to individuals and society. We'll return to the specific example of China in a moment. But first, let's consider some of the central New Testament teaching on love:

1. Love your neighbour as yourself. When Jesus is asked, 'Which commandment is the greatest?' he in fact responds by speaking of not one but two commands (Mark 12: 29-31). And the second greatest is this one, he says. When Jesus tells us to 'love our neighbours as ourselves' he is saying that just as we instinctively look out for ourselves – craving food, clothing, affection, justice and other things – so we should do likewise for others.

What does this mean for you? For us, it has meant (among other things) hosting a Christmas party in our end of the street for those who live here. It has meant supporting some neighbours in their objection to a planning application which would affect their property. I've also been giving another person in the road free piano lessons after he expressed an interest in learning. All these things are a joy. For you it will be different – but it is vital to think about.

2. Love God with all your heart, soul, mind and strength. This, Jesus says, is the greatest commandment. As Rick Warren has observed, God wants us to love him passionately (heart and soul), thoughtfully (mind) and practically (strength). It involves our emotions because we are made to express love and desire. It involves our minds because God wants us to use our brains as we follow him. And it involves our skills and talents – be that playing in a church music group, serving coffee or repairing a wall.

Tom Wright, former Bishop of Durham, declares: 'If it's true that we're made in God's image, we will find our fullest meaning, our true selves, the more we learn to love and worship the one we are designed to reflect. No half measures: heart, soul, mind and strength – that is, every aspect of human life – is to be poured out gladly in worship of the one true God. Whatever we do, we are to do for him.' This is how we are designed to function best.

3. We love because he first loved us. Of course, none of us keep these two commands perfectly. Only this morning, even before I had given our son a lift to the railway station before breakfast, I had managed to have a row with my wife. Fortunately she is rather good at 'loving her neighbour' (in this case me), and upon my return offered me a cup of tea and an apology, which was kind as I was the one who was more at fault.

The truth is that 'while we were still sinners' – and we are all sinners because we all fall short of God's standards, not to mention our own – 'Christ died for us,' (Romans 5:8). If we leave God out of the equation when it comes to loving others we will start to assess whether or not they 'deserve' our kindness. But we are all equal at the foot of the cross. And all of us, equally, have the opportunity to receive God's unconditional love, demonstrated in Christ's death, as we turn in heartfelt repentance and faith to him.

Such love has the power to transform not only individuals but societies. And so back to China, where several cities have introduced laws to encourage kindness in public situations like that of the woman who had collapsed on the zebra crossing. The nickname for these rules? 'Good Samaritan laws'. Now I wonder where that idea came from!

David Baker is a former daily newspaper journalist now working as an Anglican minister in Sussex, England. The Rough Guide to Discipleship is a fortnightly series. Find him on Twitter @Baker_David_A