If Karma decides the life, why should one pray to God?

Question: I want to ask you a question I have always pondered on. Though I am a strong believer in God and the scriptures, sometimes I cannot but think that if man suffers or prospers according to his past karma, then why does one pray to God, I mean what could be the role of God? If he has committed a crime in his previous birth for which he is undergoing suffering, is there no way out for him? Surely, praying to God and asking his forgiveness for his previous sins (which he is not aware of in this birth) may help? Please guide me.
Another question I would like to know is that suppose A harms B. It is understood that it is the fate of B and ‘dushkarma’ (bad action) of A. Both seem to be contradictory to me, if it is the fate of B then how is it the ‘dushkarma of’ ‘A’? Again if the cycle of A harming B and vice versa goes on, does that mean that neither of them are at fault?. I do not know if I am able to frame my words and doubts properly. Still I expect guidance from you.

Answer: The Theory of Karma is a complex one and needs a detailed study of it. This has different aspects.

1. It is no doubt, one has to enjoy or suffer according to the deeds he has committed in previous lives. If you fully believe in the theory of Karma, the present attitude of prayer also comes under your Karma itself. You are destined to pray also. That is why you are praying.

2. If we believe half-way and think that your present prayer is not because of the past deed, that is, now you are praying to God to help you to overcome the suffering, the God will definitely help you. He does not remove all the sufferings, but gives a wonderful strength to the mind to bear it patiently and face the problems. I wish you read Swami Vivekananda’s Karma Yoga which deals in detail all the aspects of Karma.

3. Regarding your ‘A’ and ‘B’, if ‘A’ has to do ‘Dushkarma’, there must be a ‘B’ to suffer for it. Even that is arranged according to the Karma only. That is, one who has to do ‘Dushkarma’, he will be ‘A’ and one who has to suffer, according the past karma, will be ‘B’. God only brings them together.