Romans 2:20

New International Version (NIV)

²⁰ an instructor of the foolish, a teacher of little children, because you have in the law the embodiment of knowledge and truth—

What really strikes me in this verse and the previous ones is who is doing the convincing or persuading. In other words, it doesn't seem that God or another person is setting "you" up as the authority figure but that the "you" in this passage is setting "yourself" up and the one with all the answers ready to teach and lead everyone else. I once heard a man with a gift of healing say that you should never claim a spiritual gift for yourself. You should live it out as God directs, but leave it to others to label the gift. In other words, if you have been given the gift of teaching, go ahead and teach as opportunities arise. But let other people recognize that gift and call it the gift of teaching; don't grasp for the authority that comes from telling everyone the gifts God has blessed you with and that they ought to listen to you and respond to your leadership because you have such gifts. There is a certain humility required in following this advice, especially when you feel like you have been blessed with a gift yet no one else seems to recognize it.