Why did Voldemort leave energy on Harry?

Answer 1: One year before Harry was born, Trelawney applied for a divination teacher and had an interview at the Pig's Head Bar. After chatting for a while, Dumbledore felt that she was not suitable for this position and was about to leave. Trelawney made one of the few true predictions: "The man who has the power to conquer the Dark Lord approached, was born in a family that defeated the Dark Lord three times, and was born at the end of the seventh month. The dark Lord marks him as an enemy, but he has energy that the dark Lord doesn't understand. One must die at the hands of the other, because two people can't both live, only one can survive. Those who have the energy to conquer the dark Lord will be born at the end of the seventh month. "

Severus snape was a death eater at that time. He eavesdropped on the prophecy, only to hear that "a person who has the power to conquer the dark Lord approached, was born in a family that defeated the dark Lord three times, and was born at the end of the seventh month". He told Voldemort.

Coincidentally, Harry and Neville were both born at the end of July, and their parents both defeated Voldemort three times. But Harry is a half-blood, and Voldemort chose him. Voldemort didn't know that Harry had energy (love) that the Dark Lord didn't understand, so he killed Harry when he was a child. But Harry's mother sacrificed herself to protect Harry and formed a powerful protection spell around Harry. Harry didn't die, leaving only the mark left by Voldemort.

Answer 2: When Harry was one year old, Voldemort bloodbath his whole family and killed his parents. Before he died, Harry's mother cast a protective spell on Harry. Voldemort didn't notice this spell, so when he finally tried to kill Harry with magic, the protection spell came into effect, reflecting Voldemort's magic back and giving himself a great blow. Voldemort almost died and disappeared for nearly ten years. Harry was attacked by Voldemort's spell on his forehead, leaving a lightning-shaped scar.