Jesus is the true vine, and the Lord is the gardener

John 15:1-8
Jesus is the true vine, and the Lord is the gardener. He cut off every branch in Jesus the bears no fruit, while every branch that does bear fruits he prunes so that it will be even more fruitful.
If a man remains in me and I in him, he will bear fruit; apart from me you can do nothing.
If you remain in me and my words remain in you, ask whatever you wish, and it will be given you.
This is to my Father's glory, that you bear fruit, showing yourselves to be my disciples.
Why?
Very real metaphor or example to explain our relation with Jesus and the Lord.
I am in him and he is in me, than I will be fruitful. 
God will cut off branches if it no bear fruit. God will prunes the  branch so that it will even more fruitful.
Be aware of this, to be a Christian have to be a real life of God in me, to glorify the Lord, and shows myself is the disciple of Jesus.
Jesus has given me a promise if we are in him, what we wish and it will be given you. How wonderful it is. Sometimes we have trouble or suffering, it might be is the prunes from the Lord to let us more clean and be fruitful.
How?
Reading bible and keep in mind of God's words, do it. Like a Christian to glorify the Lord.
Jesus forgave me, sometimes I will do the things you don't like, for I am a thief want to save a little money, this is my weakness.