This is how we know that we love God's children: it is by loving God and obeying his commands.
This, then, is what I command you: love one another.
If we obey God's commands, then we are sure that we know him.
But if we obey his word, we are the ones whose love for God has really been made perfect. This is how we can be sure that we are in union with God:
We know that we have left death and come over into life; we know it because we love others. Those who do not love are still under the power of death.
The command that Christ has given us is this: whoever loves God must love others also.