God did not create the Devil. Instead, God created the angel who later became the Devil, also known as Satan. Jesus implied that at one time the Devil had been truthful and guiltless. Originally, then, the Devil was a righteous angelic son of God.
The angel who became the Devil chose to oppose God and incited the first human pair to join him. He thus made himself Satan, which means “Resister.”
Like the rest of God’s intelligent creatures, the angel that became the Devil had the freedom to choose between doing right and doing wrong, but he developed a desire to be worshipped. His desire for glory was stronger than his desire to please God.