Killing in the name of their god

Religious extremists often kill in the name of their god, thinking that they are doing their god a service. For example, a Muslim extremist might cry, "Allahu akbar!" or "Allah akbar!" (which basically means "God is great") just before he blows himself and others up, or when he has just decapitated a Christian or Jew.

Above: Religious extremists killing in the name of their god.

John 16:2
2 They will put you out of the synagogues; yes, the time is coming that whoever kills you will think that he offers God service.

Jesus warned His disciples that "the time is coming that whoever kills you will think that he offers God service". Although He was referring mainly to the religious Jews (such as Saul), who would persecute His disciples and throw them out of the synagogues, I find it interesting that in the post September 11 era, this warning still applies.

What else did Jesus say about these people?

John 16:3
3 And these things they will do to you because they have not known the Father nor Me.

He said that these people "have not known the Father nor Me".

So if you are a religious extremist and you are reading this, according to Jesus (whom Islam regards as a prophet), you do not know the Father nor do you know Jesus.

The opposite is true

In Christianity, God does not require you to die for Him. However, He requires you to believe that He died for you.

John 3:16
16 For God so loved the world that He gave His only begotten Son [Jesus Christ], that whoever believes in Him should not perish but have everlasting life.

Romans 5:8
8 But God demonstrates His own love toward us, in that while we were still sinners, Christ died for us.