'Evil One' in the Bible

I write to you, fathers, because you have known him who is from the beginning. I write to you, young men, because you have overcome the evil one.

I wrote to you, little children, because you have known the Father. I wrote to you, fathers, because you have known him who is from the beginning. I wrote to you, young men, because you are strong, and the word of God abides in you, and you have overcome the evil one.

and not be like Cain who was of the evil one and murdered his brother. And why did he murder him? Because his own deeds were evil and his brother's righteous.

We know that anyone born of God does not sin; but he who was born of God keeps him, and the evil one does not touch him.

We know that we are of God, and the whole world is under the power of the evil one.