Right now, at this very moment, we have absolutely crucial decisions to make. Innocent people are being butchered just because they are Christians, or Yazidis, or just deemed by this particularly vicious brand of Islamism to be unworthy of life. I have never before seen such barbaric scenes in my news feeds: videos of trucks carrying severed heads, people being crucified. ISIS seem to be proud of the despicable evil they are carrying out in Iraq.

We look back at other atrocities such as the Rwandan genocide, and even the Holocaust, and we wring our hands and kick ourselves for what we could have done. We should have bombed the railway lines that were carrying Jews to their death, for example. We should have done more, we think. We could have, we should have.

So here's our chance to fight such evil. Right now, we have an opportunity to act and stop these terrible atrocities being carried out. And the drumbeats are starting to sound: "We must send troops. We must arm the Kurds. We must recall parliament. We must bomb the Islamists. We must, we must."

This is the only moral response, it seems. But we need to be careful that evil does not begat more evil. Remember that there will be Islamists today who were partially radicalised by being told of some of the despicable things done in our name, such as the abuse of prisoners at Abu Ghraib. They observed such abominations, and thought that fighting the West must be the right thing to do. Similarly, recent events in Iraq are so terrible that the danger is we'll be mobilised into the wrong kind of action against the perpetrators.

We want, right now, the people whose lives are at risk in Iraq to be rescued. We want them to be spirited out of the place, we want to go and imprison the people who are killing and torturing. We want Iraq to be governed by reasonable people, we want ISIS as an organisation to disappear. Of course we do. But are we the ones who would have to carry this out? It's British and American soldiers who would be doing such acts, and they'd not just risking their lives by fighting. If caught, they would be almost certain to face a merciless and gruesome end. Would you personally be willing to do this? If not, then we shouldn't be so eager to send others to this fate. Let's hope that there are willing rescuers. But it's easy to call for others to put their lives at risk: not so easy to do it ourselves. Of course it's similarly easy to argue for pacifism when it's not your family who is facing brutal slaughter. Doing nothing is absolutely not an option. Let's not go for easy rhetoric.

We don't have a great record of overcoming Islamism with our high-tech weapons and the lives of our young soldiers. Is there any reason to think that this time, we will do a better job? Well, there have been reports that air strikes have helped Kurds to recapture land from ISIS. So, if there is anything we can do that we know will succeed in rescuing the people of Iraq from this tyranny, then it must be done urgently. However, note in this article, that ISIS is using arms that the West originally gave to the Iraqi army. It's our own weapons we're now seeking to neutralise. Our military response backfired terribly in that case. So assuming that might is right is naïve: we've got to be measured, and listen to the experts. Let's urge our leaders to do this, and fast. We need our politicians and our military strategists to come back from holiday and make this issue a number one priority: urgently discussing what the options are, and what action will be genuinely effective.

So what else can we do on a personal level? We need to be donating money to the people who are helping the refugees of this scandal. Here are some practical steps to take.

But most of all we need to pray. We need to really, really, get on our knees and pray. We don't trust in might and power: we trust in the One who is the ultimate measure of justice. We don't trust in chariots, we trust in the name of the Lord our God. We don't trust in violence, nor ideological pacifism, nor government. We trust in the Saviour King who faced all the evil in the world, and won. Let's pray like we've never prayed before. Let's pray for the evil to be stopped right now, and that these terrible events would not lead to further evil being justified.

• For help focusing your prayers, try this from Open Doors, this from Christian Aid or this from pastor Garrett Kell