If we love one another, God lives in us and his love is made complete in us

 1 John 4:7-12

Dear friends, let us love one another, for love comes from God. Everyone who loves has been born of God and knows God. Whoever does not love does not know God, because God is love. This is how God showed his love among us: He sent his one and only Son into the world that we might live through him. This is love: not that we loved God, but that he loved us and sent his Son as an atoning sacrifice for our sins. Dear friends, since God so loved us, we also ought to love one another. No one has ever seen God; but if we love one another, God lives in us and his love is made complete in us.

Why?
The source of the Love is Jesus loves us. Jesus Christ loves us through his life as atoning sacrifice for our sins. 

The action of love to us is to love one another. For love comes from God.

No one has ever seen God; but it we love one another, God lives ins us and we may show the love of the Lord to others.

The love of people is always for the benefit of their own, but the love of Jesus is a love of sacrifice, this love comes from our hearts and from the love of Jesus Christ.

How?

How to show my love to others, take care and listen to the needed person.