Who is God from A Grief Observed and what is their importance?

Lewis spends a good deal of time in this book contemplating the aspect of the character of God that inflicts pain, and trying to reconcile that with the God who loves His children and works constantly for their good. He describes feeling shut out of heaven in the beginning of the book, when his pain is most acute, as if God only makes Himself available when people have praise and thanks for Him, but not when the need for intervention and comfort are most great.

As the book progresses, Lewis ultimately comes to understand that God designed life on earth to be a semi-blind walk through a story all the parts of which only He can see, in bodies bound to distract and cloud our thinking, and so life will necessarily be painful and confusing. He compares people to animals, and God to the veterinarian, inflicting pain in order to cure us, and offers the hope that we will see perfectly the purpose for the pain when we are free of the distractions of our bodies and limitations of our minds. He comes to understand that God designed the ultimate separation of spouses as the necessary conclusion of marriage, as naturally as adulthood follows adolescence. Instead of an absent, arbitrary, or aloof deity, God becomes a deliberate, attentive, omnipotent, and compassionate teacher, tenderly guiding His children through the seasons of life and into His presence in eternity.