Concept of God is the very basis of every religion but it differs vastly between religions. As an integral part of our journey towards salvation, the different religions have defined God to be of different type and kind. There must be a concept of God in every religion, for without it everything about its beliefs and rituals would be meaningless. In all religions God is omnipotent and omnipresent. The difference lies in its other features. In some religions it is feminine and in some others it is masculine. In some it resembles humans and in some others it is quite unlike. In some it is of a particular form and in some others it is formless. And more interestingly, and of more consequence, God has definite characteristics in some that contradicts completely with those in others.
In today's world, if one is religious it means that one is a follower of an existing established religion. And to be irreligious means that one does not believe in any of the existing religions. But this is not correct. Each one of those who are termed as irreligious may still have their own versions about God, unless of course one is an atheist. An ideal atheist must be one like Bertrand Russell who did not see any reason to believe in any form of God at any stage in his adult life (at least he said so). In a way atheism must also be considered a religion just like zero being considered a number. Perhaps Indian is the only civilization in the whole world which also accommodates true atheism as one of the means to realize God i.e. about its non-existence.
In many of the organized religions of the world, the concept of God is a proactive one. This is very clear from the well known expressions in everyday use among its followers. Most Compassionate God and Most Merciful God obviously refer to someone like us but with unlimited compassion and mercy towards the followers. And that our actions are always under the surveillance of God. Our goodness is rewarded and wrongness punished. But the questionable feature lies in the possibility of compassion or mercy for those who look for it following their ill deeds. To err is human but to look for an escape without any punishment is also equally human. It is this unfairness of humans that is most effectively and efficiently (mis)used by the designers of organised religions. And most people fall for such attractive gimmicks even when it relates to God.
In organized religions, God is considered an ever vigilant and efficient monitoring agency. Any form of monitoring leads to control and it is this remote control that is believed to keep Man in the right path. But what can happen if the control mechanism accommodates failures and adjusts for mistakes? The system will ultimately fail. The analogy of God with a vigilant but accommodative control system is an apt one. An ideal control system should severely punish deviations and reward compliance. And it should never allow any compromise with detected deviations lest wrong models become possible and wrong precedents would get set. The whole mechanism would collapse one day under the weight of accumulated wrongness. Unfortunately this is what happens in the case of followers of such wrong concepts of God.
In sharp contrast to the concept of a proactive God is the one with reactive features. This clearly means that either a reward or a punishment follows each one of our actions. A reactive God is normally dormant and becomes active only when an action takes place. It does not act of its own initiative but will only react to our actions. The concept of a reactive God fits in well with those of an independent fate or destiny. Each and every object in this universe has a purpose and follows a course of action. In the case of the animate we call this course as fate or destiny which they are born with. A reactive God will not have much role in the current status of any being but will only monitor and control the incremental effect negatively or positively based on the value of their actions.
The most rational way to explain fate and destiny as something we are born with is the theory of rebirths. Fate and destiny of anything animate at any point of time is on account of its accumulated karma from its earlier lives and deeds so far in the current life. The clear advantage in this concept of a reactive God is its unambiguous positive encouragement for anything good and punishment for any wrongdoings. If we can easily get away with our misdeeds by fooling an omnipotent & omnipresent God by playing on its compassion, it may be better not to have any God at all. God must be an all knowing and powerful yet impartial judge for all our doings at each and every moment in our lives. Eye for an eye must form the basis of natural justice dispensed by God.
As a rational being I consider it the solemn duty of each human being to think his or her own way through the concepts of God available in front of us. The concept of a compassionate or merciful God looks abhorrent to me personally. If I knowingly make a mistake I must be prepared for its punishment too. Those who think that the most benevolent, most merciful and most compassionate God would pardon or lower the punishment just because they are smart enough to repent in time and offer a confession are too ridiculous and cruel. Such a God could not have sustained life for so long in this world of struggle and competition. A purely reactive form of God that is tough, fair and just is the best one that appeals to me. Sinning must never go unpunished and if it is possible to escape the consequences of sin, then there is no God at all.