A.T. Robertson Commentary 1 John 2:13

"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." — 1 John 2:13 (ASV)

Fathers (πατερες). Those mature believers with long and rich experience (εγνωκατε, ye have come to know and still know).

Him which is from the beginning (τον απ' αρχης). See 1:1 as explaining this crisp description of the Word of life (cf. John 1:1–18).

Young men (νεανισκο). The younger element in contrast to the fathers, full of vigor and conflict and victory.

Ye have overcome the evil one (νενικηκατε τον πονηρον). Perfect active indicative of νικαω, a permanent victory after conflict. The masculine article τον shows that the prince of darkness is the one defeated in this struggle, the devil plain in 3:8,10 (John 8:44; John 13:2).