Why do Hindus say God is omnipresent?
All Hindus believe God is omnipresent. One cannot see a tree hidden within a seed. The butter cannot be seen in milk. One cannot see the oil in mustard. The fragrance cannot be seen in the flower. One can feel pain, but cannot see it. We cannot see the ills within us. In the same way, though God is omnipresent, we cannot see Him.
Just as the soul resides within the body, God resides within the whole universe. We cannot see Him because of our ignorance. With knowledge and devotion we can experience our proximity to Him. Just as there is water everywhere underground, but we can source it only through a well, in the same way, although God is everywhere, we can reach Him only through devotion and prayer.
In the Bhagavad Gita, Sri Krishna says, "I am present in perfect form everywhere. However, everyone perceives Me in harmony with the devotion in his or her heart. One can perceive Me only through the heart."
In the Bhagavad Gita, 13/13, it is said:
God is everywhere. He can touch and feel everything. He can see everywhere. He can hear everything. No place is without Him. He can understand everything. There is nothing that He cannot see. There is nothing that He cannot accept. He can reach everywhere.