On Wednesday afternoon, March 22, 2017, London’s Westminster Bridge was crowded with pedestrians. A grey Hyundai 4x4 suddenly careened off the road and plowed into the crowd on the sidewalk, mowing down whoever was in his way. Three people were killed, plus the terrorist, and over 40 people wounded, many of them seriously.

Among the victims were a group of French students from Saint-Joseph high school in the northern French town of Concarneau who were on a school trip visiting London. Three police officers who were walking across the bridge after a commendation ceremony were also hit. A group of students from Edge Hill University in Ormskirk, Lancashire, in Britain were on a two-day educational trip to Parliament, and were also injured.

Keith Palmer, inset

Once the terrorist reached the Houses of Parliament, he rammed the buildings’ gates, exited his car and stabbed to death Keith Palmer, a 48-year-old policeman, before being shot by police. Parliament, which was in session, was placed in lockdown.

As Britain reeled from this attack on its government and our hearts go out to its citizens, many of us are wondering what we can do in the wake of this murderous rampage. Here are four ways to respond.

1. Never Excuse Terrorism

The London attack came a year after terror attacks in Brussels, which claimed 32 lives. In the hours after the carnage in London, British authorities took the unusual step of calling it a likely terror attack. Although no official blame had been announced yet, in the hours after the attack ISIS supporters around the world celebrated the attack on Twitter, writing “Allau Akbar” next to pictures of injured victims lying on the ground, sending messages hailing the “blessed London attack” and pictures of the attack with smoke billowing out and the message “Our battle upon your land.”

If the attack does end being perpetrated by a radical Islamist, it will hopefully cause the many Brits who have excused and apologized for Islamist terror when directed against Jews and Israel to rethink their positions. Jeremy Corbyn, leader of Labour, Britain’s main opposition party, is a cofounder of the Stop the War Coalition, which has organized virulent rallies attacking Israel, featuring chants glorifying terrorist organizations: “We are all Hamas now!” and “Victory to Hamas!” rang out in London when Britons protested Israeli military actions in Gaza.

The tragic London attack serves as a crucial reminder that we must stand firm against Islamist terror, wherever it strikes. Justifying or trying to excuse it when it targets Jews encourages terrorism and emboldens those who seek to harm us.

2. In the Face of Terror, Act.

In the minutes after the attack, MP Tobias Ellwood emerged as one of the heroes of the day. The 50 year old Foreign Office minister performed CPR on a wounded policeman and tried to staunch the officer’s stab wounds for 15 minutes until help arrived.

MP Tobias Ellwood

Mr. Ellwood’s brother, Jonathan, was murdered in the Bali terrorist bombings in 2002, in which 202 people, including 27 Britons, were murdered by Islamist terrorists. Britain’s Middle-East Minister, Mr. Ellwood declared in Parliament weeks ago “that it is unacceptable for Israelis going about their business to be subject to some of the brutality and the murder we are seeing. Israel has the right – in fact, I would go further and say it has the obligation – to defend its citizens.”

3. Step up Protection

In the hours after the London terror attack, British police increased patrols in heavily Jewish parts of London. When a suspicious package was seen near the offices of a Jewish newspaper in the British city of Manchester later that day, police evacuated a bus and cordoned off an area to investigate.

This elevated caution isn’t misplaced. In recent months, ISIS has published a terror manual to teach would-be terrorists how to use trucks as weapons to “crush many victims” in attacks like those in Berlin and Nice. In the hours after the attack, ISIS supporters praised the London terrorist as a “soldier”. Given this risk to our safety and way of life, we each have to demand that our communities are given protection, particularly high-risk environments such as Jewish schools and synagogues.

4. Do Good in the Merit of the Victims

When things seem dark, the Jewish response is to search for ways to bring extra light into the world. Lighting Shabbat candles (or, if you already light candles, resolving to light them early) in the merit of those who were killed and injured is one way to fight the forces of evil who perpetrated this attack. Learn Torah or perform an extra good deed as a way of countering violence by bringing more goodness into the world.