“By this we know that we love the children of God, when we love God and keep His commandments.”
John reverses the sequence of 4:20,21 in this verse. In chapter four, he put forth the idea that to love God is to obey Him. Here he says, “We love God when we love His children.” When we put these two passages together, they show that love for God and love for the family of God are mutually vital to each other.
By this we know
We should translate this phrase this way, “By this we come to know.” By ascertaining the following two facts, we can gain assurance that we love the family of God.
As love for fellow Christians is the test of our love for God, our love for God is the test of love for fellow Christians. Conscious love for God is the inward spiritual criteria for whether we love the family of God. We gain assurance that we love God because we love fellow Christians; the reverse is also true, that we love Christians if we love God.
that we love the children of God,
Implicit in love for the family of God is love for God and keeping His operating principles for life. Love for God and love for the family of God works as a double-edged sword; it works both ways.
1 jn 3:14, “We know that we have passed from death to life, because we love the brethren. He who does not love his brother abides in death.”
when we love God
The word “when” means whensoever. The idea points to every occasion we fulfill the two conditions of this verse. This is a general principle that applies to all occasions.
The Greek of “whensoever” is also definite, introducing a precise test. Each act of love to God from obedience to His commands forms new evidence of love for His children. This love is effective whenever the prescribed condition is fulfilled. Constant completion of love for God and applying His Word involves loving fellow Christians. As ever-new occasions present themselves, this offers new evidence that we love Christians.
Love for God and His Word is the evidence that we love the family of God.
If we want to know whether we love fellow Christians, we need to ask ourselves if we love God and apply His principles to experience. The test of whether we love the family of God is whether we love God and His Word. Love is always faithful to God’s principles.
Love willingly confronts Christians out of phase with God. True love does the best for the other person, even though it may be a painful process. We do this by God’s norms and not our personal preferences. This action may offend the other party. We may disagree with each other but disagreement does not mean that we do not love them. Love does the unpleasant thing because it operates on the higher plane of honoring God’s principles above everything.
We know that we love God because we love the brethren. The reverse is also true that we know we love Christians because we love God. This is set forth in the old spiritual: “Give me the old-time religion, makes me love everybody.” That is what happened to the Philippian jailor. When he was born again, he took Paul and Silas out of jail, washed their stripes, brought them to his house, and fed them.