Personally I am struck by the essential similarity between a massacre delivered on the ground and one delivered from the sky.
Maybe a fundamental question raised by such events is the old one about what such actions tell us about God, and about mankind.
It's a fundamental starting point to Christianity that people were created in God's image but that this image has become distorted and spoiled. In other words people are a strange mixture of good and evil, right and wrong, light and darkness.
So the basic question in Christianity is not why God allows things like these brutal massacres to happen, but what is he doing about them?
One answer lies in the bravery and selflessness shown by many in response to the horror around them - I am sure that in both Paris and Beirut there were far more people of courage and compassion than there were killers with their hatred and destruction.
But underlying that is a long term transformation of humanity: a preparation for a final cleansing which will bring healing and new life to a struggling world. The key enabling moment in that transformation was the death and resurrection of Jesus.
But that was nearly two thousand years ago! I trust that there is good reason for the long wait for Jesus' return and the transformation of heaven, earth and humanity that he will bring. Nevertheless, with the prophets of old, at times like this I have to ask:
"How long, O Lord?"
PS: Clicking on the above image - a pyramid in Giza lit up with the flags of Russia, Lebanon and France - takes you to an extremely depressing list of terrorist attacks so far in 2015. One thing I do notice is that the vast majority are carried out by adherents of one particular extreme sect of Islam against members of more mainstream groupings within Islam - especially against Shia. Blaming Muslims in general for these attacks is about as accurate as blaming Christians for the actions of Westborough Baptist Church; although Wahhabist Salafists do get a lot more funding, thanks to Saudi oil money.