A new commandment I give to you, that you love one another, even as I have loved you, that you also love one another. By this all men will know that you are My disciples, if you have love for one another,
- John 13:34-35

How will all men know if we are Jesus’ disciples? Jesus made it clear above.

This is My commandment, that you love one another just as I have loved you.
John 15:12

Do you think Jesus repeated Himself for emphasis? Don't we need the emphasis?

“He who has My commandments and keeps them is the one who loves Me; and he who loves Me will be loved by My Father, and I will love him and will disclose Myself to him….. If anyone loves Me, he will keep My word; and My Father will love him, and We will come to him and make Our abode with him.”
- John 14:21 & 23

Jesus makes it clear that only those who obey him have any right to claim that they love him. In other words, contrary to what anyone may claim, where there is no obedience, there is no love.

“But so that the world may know that I love the Father, I do exactly as the Father commanded Me…,”
John 14:31

How does Jesus prove his love for God? He obeys, holding himself to the same standard he would have us to apply to ourselves.

Jesus’ apostle John, having faithfully recorded his Lord’s words as we have noted them above, also wrote:

“By this we know that we have come to know Him, if we keep His commandments. The one who says, ‘I have come to know Him’ and does not keep His commandments, is a liar, and the truth is not in him; but whoever keeps His word, in him the love of God has truly been perfected. By this we know that we are in Him….”
- 1st John 2:3-5

“By this we know that we love the children of God when we love God and observe His commandments. For this is the love of God, that we keep His commandments; and His commandments are not burdensome,”
- 1st John 5:2-3

“And this is love, that we walk according to His commandments,”
- 2nd John 6

Jesus said our obedience proves our love for him, as in, 

“Why do you call me ‘Lord, Lord’ and do not do what I say?”
- Luke 6:46. 

Hmmmmmm….. good question.