God is spirit.
He is not just the 'law of life' even though He makes the laws.
we cant see God but God has revealed to us in the flesh when Jesus came on earth.
After Jesus was resurrected and ascended to heaven, He sent his holy spirit (some translations of the Bible say holy ghost) A ghost or spirit is by nature, invisible. we cant always see it or touch it. But we can sense it, The Holy Spirit is God...Has always been part of God from His first breath. another greek translation is pneuma...breath.
Hope that helps your understanding...we get the fuller picture of God in the Bible which is why Christians read it all the time and dont just rely on our senses. After all He is the one who inspired scripture.