why did voldemort kill harry's parents

Voldemort killed Harry's parents because they stood in the way of him reaching and killing baby Harry, whom a prophecy foretold would have the power to defeat him. The prophecy, partially overheard by Voldemort, indicated a child born at the end of July to parents who had defied him three times would be his equal and potentially vanquish him. Voldemort targeted Harry specifically because he saw a resemblance to himself in him, making Harry the child he marked as his equal. In the attack, James and Lily Potter were killed because they tried to protect Harry, and Voldemort gave Lily a choice to live if she let Harry die, but she sacrificed herself to save him, which created a protective magic that saved Harry from Voldemort's killing curse. Additionally, Voldemort's decision was influenced by betrayal from Peter Pettigrew, who revealed the Potters' location, allowing Voldemort to attack them. This event set in motion the prophecy's fulfillment and Voldemort's eventual downfall.