I want ask why some Christian need to work harder (more struggling and suffering) than others to produce spiritual fruit?

to be fruitful

Dear Ray,
I think a real faithful Christian is not just like the other people. He does not need to be worry for producing fruits in his life. Because all usual activities which is done by me, is in the supervisions of my own will. And because my own will is the will of human, that act will not be clean and separate of creatures and then is not spiritual. For this reason my act will not be worthy for my Lord, even though on my opinion it is the best act in my life.
By the way, my faith is from hearing of the words of Jesus and my duties are as the same, he wants me to do something when I am talking with him in my prayer, and then I have an order to do that, or he will tell me his orders in other ways, each way he wants himself. What is my duty?  I must obey him completely after hearing his orders or inform about his laws and ways. For example I do know that he asked me to leave all my worthy things in the world for him. And I can not accept that, ok, I must ask him to decrease the worth of world, in my heart and increase his own love in my heart instead. This will be done in a completely privet pray to him. If I can not obey his laws, and love my enemy, do not look after something to eat and something to wear and …., I can not be his friend, or his son. Jesus will not accept me in his heaven. But if I decide to do as he wants, I can see myself as his friend and be completely trust on my sinless, because of his forgiveness.
As you see, to production fruits, we must be lead by Lord, and this is the Lord who can understand which of us must work hard and which must do less.
He knows every thing and all of us will be luck and safe, if only do not decide to make our desires, and let him to make plans for us.
Every body knows more, better to work harder by decision of God.
Every body has more patient, must work harder by decision of God.
Every body can be more effective must work harder by decision of God.
And so on. by all these we will be useful for Lord and his lost sheep. we will be interesting for the people who wants to see the kindness of God.
In the name of Jesus