“We know love by this, that He laid down His life for us; and we ought to lay down our lives for the brethren.”
(1 John 3:16 NAS95)

We believe in and worship a God who suffered and sacrificed for us.  John says that we ought to take that example of suffering and sacrifice and carry it to our fellow believers in the form of lives laid down on their behalf.  How this looks and what shape it takes will depend upon our situation, but one thing is for sure laying down our lives will cost us something.