To pose such a portentous question as the above could be only attributed to a cynic, who does not view God in the proper perspective. It could steel from his ignorance of God, and the universal marginalization of the forces of good, being dominated by the forces of evil. The triumph and adulation of these evil forces are destroying his belief in goodness and truth, making him wonder at times of god's existence.
God is neither a physical nor an abstract creature. He is not there in temples, churches, idols or the pilgrim spots that one religiously visits. He is but a manifestation of all things good in life and resides in each and every living creature on earth. The Bible, therefore, says "God created man in his own image, in the image of God, male and female created he both".It was this eternal truth that Siddhartha set out to find after renouncing his kingdom. Only to later realize on his enlightenment, that what he had to set out to seek was but present in him. This eternal pursuit of man to know God give rise to spiritualism, and the growth of religion. Thus in the Hindu mythology, we have the great epic of Ramayana which motivates to emulate the noble ideals of Lord Rama. It effectively brings out the universal truth of victory of good over evil.
It is indeed an antithesis of all religions, that we find people fighting among themselves to prove the supremacy of their religion. This hatred has led to the growth of religious fundamentalism, which is posing a grave danger to mankind. The religious zealots behave like savages, baying for each other's blood, an act not sanctified by any religion. Charles Colton rightly remarked, "Man will wrangle for religion, write for it, fight for it, anything but live for it."
To compound to the growth of religious fundamentalism,there is a progressive domination of the forces of evil that seem to go unpunished all around us. On the other hand, the forces of good are seen to be retreating and going unrewarded. Thus we find the mafias and criminals infiltrating the corridors of power and prospering, while the good and the pious, are being gradually sidelined, and trampled upon. We are all aware of the corrupt politicians and bureaucrats, flourishing in the government at the expense of the poor taxpayer. They resort to untruth, corruption, and even crime, never to meet their nemesis. It is this skepticism that at times raises the doubt of God's existence.
The eternal truth is that all religions lead us to but one God. Godliness resides in every human soul and can be nurtured and developed through love and compassion for our fellow beings. This is the basic percept of all religions. One must also not lose heart on seeing the forces of evil presently having the upper hand for in the ultimate analysis good and truth will only prevail. In the words of H W Longfellow
"Though the mill of God grind slowly,
yet they grind exceedingly small;
Though with patience He stands waiting,
with exactness grinds He all."
One must therefore not give way to despair, and move away from godliness, as it only can make us happy, and bring peace and prosperity to the strife-torn world. Our belief in God and godliness cannot die, as long as there is life on earth. To have any illusion, on the contrary, would tantamount to inviting disaster and doom.