The big ‘G’ is God, father to Jesus Christ and part of a triune spiritual entity that created and loves us all. This big ‘G’ is omnipotent (all-powerful).
Ok, enter main point, this big ‘G’, God, is able and makes us willing. He is infinitely able to draw out of us the character traits that belong to the Holy Spirit that is placed in us when we believe in the already finished work that made provision for our hopelessly incapable souls. Obedience is SUCH a big catharsis into the realm of peace, and ability. It is not an ability to obey that changes our circumstances, gives perspective and transforms our mind. We are never willing to do this within ourselves. Rather, it is our obedience and submission that becomes within itself the catalyst. Whether we want to, we must obey, it causes change in our hearts, situations and those around us.
I can detail experiences, especially of forgiveness where I had no inclination to forgive someone and telling God of this lack, he gave an instruction rather than desire. Upon following the instruction, changes came about both in my heart towards the person as well as them towards me.
Obedience is an instinct. We don’t psyche ourselves up to obey, we ‘just do it’ because the big G is capable of making us both ‘able’ and ‘willing’ but we must FIRST obey.