“But whoso keepeth his word, in him verily is the love of God perfected: hereby know we that we are in him.”
King James Version (KJV)
2:5 But whoso keepeth his word - His commandments. Verily in him the love of God - Reconciled to us through Christ. Is perfected - Is perfectly known. Hereby - By our keeping his word. We know that we are in him - So is the tree known by its fruits. To know him, to be in him, to abide in him, are nearly synonymous terms; only with a gradation, - knowledge, communion, constancy.
1Jo 2:5 But whoso keepeth his word, etc. It is by keeping his commandments that the love of God is made perfect in us. Obedience is the result and proof of love, and also gives love the opportunity to flow over the whole life. Compare Joh 14:21. Hereby. By our loyal obedience.