Answer:
You cannot keep me until you have given me. What am I?
I roam through the lands hoping to rescue my love. I search high and low and will stomp on you if you get in my way!
I am a rock group with four members. All dead one was assassinated.
Never ahead, ever behind, yet flying swiftly past, for a child, I last forever, for adults, I'm gone too fast.
You use a knife to slice my head and weep beside me when I am dead.
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.