The prerequisite to being used by God is having your faith tested with trials.  Faith that is not tested cannot be trusted and that is why God uses every part of our lives, the negative and the positive, to make us complete and whole in Him. There is no other way, and that is why we must accept the thorns with the roses; the storms with the calms; the sight with the blind; the pain and the pleasure; and the noise and the silence. Every part is necessary, and as the Apostle Paul wrote, “Being confident in this very thing, that He who has begun a good work in you will COMPLETE it until the day of Jesus Christ” (Philippians 1:6).