Charles Spurgeon Commentary 1 John 2:11-14

"But he that hateth his brother is in the darkness, and walketh in the darkness, and knoweth not whither he goeth, because the darkness hath blinded his eyes. I write unto you, [my] little children, because your sins are forgiven you for his name`s sake. I write unto you, fathers, because ye know him who is from the beginning. I write unto you, young men, because ye have overcome the evil one. I have written unto you, little children, because ye know the Father. I have written unto you, fathers, because ye know him who is from the beginning. I have written unto you, young men, because ye are strong, and the word of God abideth in you, and ye have overcome the evil one." — 1 John 2:11-14 (ASV)

But he that hates his brother is in darkness and walks in darkness, and knows not where he goes, because that darkness has blinded his eyes. I write to you, little children, because your sins are forgiven you for his name's sake. I write to you, fathers, because you have known him that is from the beginning. I write to you, young men, because you have overcome the wicked one. I write to you, little children, because you have known the Father. I have written to you, fathers, because you have known him that is from the beginning. I have written to you, young men, because you are strong, and the word of God abides in you, and you have overcome the wicked one.

Having overcome him, at first by your faith in Christ you still go on to conquer him by abiding in Christ.