Some of us will be martyred for loving Jesus (Matthew 24:9), and the killers will even think they are honoring God (John 16:2). But God is Sovereign (I Chronicles 29:11-12), His purposes cannot be thwarted (Job 42:2), and He will work even grizzly ISIS murders for the good of His children (Romans 8:28).
Our slain brothers will be given justice (Revelations 6:9-11), God will comfort His grieving children (2 Corinthians 1: 3-4), and in the mean time we love & pray for our enemies (Matthew 5:44).
To be a Christian is to be willing to have our throats gashed for Jesus' sake. If that thought is absurd to you, you aren't His. If the thought is frightening--that's you and me both; but God will give us grace to endure to the end.
Come quickly Lord Jesus.