Anger begets more anger. So said Mahavira, the 24th tirthankara of Jainism, more than 2,500 years ago.

Those words are still true today as demonstrated by the now infamous epaysg advertisement and the video response by YouTuber Preetipls (also known as Preeti Nair) and her brother, rapper Subhas Nair.

In case you missed what happened, here's a quick summary. E-payment website epaysg engaged an ad agency to do an advertisement. The storyboard involved showing people from different races all using e-payment to demonstrate that e-payment is for everyone.

So far, so good.

The problem was that instead of having actors from different races to portray the multiracial characters, Mediacorp artist DJ Dennis Chew, who is Chinese, was engaged to play the characters of all races - including appearing as a Malay lady in a tudong and an Indian man, with visibly dark skin or "brownface".

In earlier decades, something like this may have passed without comment. Some might even have found it funny. Older Singaporeans will recall the Black And White Minstrel Show which was quite acceptable back in the 1960s and 1970s. But societal attitudes have changed.

In this day and age, one would think the creative team would have known better but apparently not. Unsurprisingly, there was a backlash against the "brownface" portrayal. The ad was then pulled. It could - and should - have ended there but it didn't.

In response, Ms Nair and her brother made a video with a rap insulting Chinese Singaporeans, using four-letter words and vulgar gestures directed at Chinese and posted it online.

In the video Ms Nair wears a T-shirt with the words "Yes, it's because you are Chinese", referencing an earlier video of an altercation between a Chinese passenger and a Malay Gojek driver which went viral.

The "brownface" ad was distasteful. But the video went further and crossed the line.

At that point, the authorities stepped in - the Infocomm Media Development Authority issued a notice to the video's publishers to take it down, with which they have since complied. The public has been advised not to further circulate it.

The police are now investigating the matter.

Some may ask why it is necessary to do this - after all it's just one video; the rap is a parody of an existing song and it's just a bit of fun. Isn't the Government overreacting? But that's the point. It wouldn't be just one video. Parody or not, its content is offensive. But more than that, it doesn't take any great leap of the imagination to see where the Preetipls video would lead: Those taking offence at this video would then want to make further retaliatory videos targeted at Indians or other races and so on.

If you allow one, you have to allow others. There would be a ratcheting up of the decibel level. Words would be spoken that cannot be unsaid; hurts would be inflicted that cannot be easily healed. And that would be the start of the downward spiral to hate.

We see this happen time and time again in other countries. We are determined not to go down that route. We have racial and religious harmony in Singapore but this does not mean that there are completely no issues. Issues of race, religion and cultural differences do exist, as reflected by the various surveys from time to time. But the way to address them is not by hurling abuse and generating more anger. As Senior Minister of State Janil Puthucheary pointed out, two wrongs do not make a right.

Anger and hate are easy to rouse. But the damage caused takes a long time to repair. Conversely, goodwill and peaceful relations take a long time, decades, to build. But destroying them can be done in a matter of seconds. The peace and harmony we enjoy in Singapore is not because we are lucky. It's also not because everyone acts with awareness and scrupulous care not to give offence to others - as the recent incidents show. It is because we work hard at it, intervening directly if need be.

Maintaining racial harmony is hard work. It requires constant monitoring and maintenance. It requires all races to make a conscious and concerted effort to be mindful of the feelings of other races, to make sure that we act fairly and without discrimination. It requires strict laws and the willingness to enforce them. When in the wrong, it requires the ability to recognise that and apologise with sincerity.

It also requires something more, which is reflected in the complete quote of Mahavira which is this: "Anger begets more anger, and forgiveness and love lead to more forgiveness and love." To be a truly multiracial and harmonious society, we need to focus on the latter, not the former.

•Indranee Rajah is Minister in the Prime Minister's Office and Second Minister for Finance and Education.