Jesus said, “Let me give you a new command: Love one another. In the same way I loved you, you love one another. This is how everyone will recognize that you are my disciples—when they see the love you have for each other.” (John 13:34-35)
Jesus isn’t talking the feeling of love or about an emotional kind of love. Jesus is saying that we will be recognized by our actions of love. Our obedience and sacrifice are the true marks of love; not our feelings.
I like the way J. I. Packer sums this principle up in his book Concise Theology:
“The hallmark of the Christian life is Christian love. The measure and test of love to God is wholehearted & unqualified obedience; the measure and test of love to our neighbors is laying down our lives for them.
Love is a principle of action rather than of emotion. It is a matter of doing things for people out of compassion for their need, whether or not we feel personal affection for them. It is by their active love to one another that Jesus’ disciples are to be recognized.”