In Matthew 20 James and John come to Jesus. He asks them: 'What do you want me to do for you?' They wanted to sit at his right and left hand in Jesus' glory. In the next pericope Jesus comes to Jericho and is verbally assaulted by two blind beggars (one of whom is probably Bartimaeus: see Mk 10). Asking for mercy, Jesus approaches them and asks: 'What do you want me to do for you?' They wanted to receive their sight.
Two stories. Two pairs of men. Two times Jesus asks: 'What do you want me to do for you?' And both pairs of men are blind. James and John could see physcially but were blind spiritually, evident in their request for glory. The two beggars were blind physically but could see spiritually, evident in their request for mercy.
And Jesus granted it. In fact he not only granted the beggars sight, he brought along James and John, too. We'll be able to talk with all four of these men in the new earth someday. But why? How can it be that such blindness, whether physical or spiritual, can be healed in sinners like James and John, like the beggars, like you and me?
Because Jesus said 'What do you want me to do for you' a third time. Nestled into Matthew 20 (and Mk 10) is Jesus' statement that he came to give his life as a ransom for many. Jesus asked the Father what he wanted, and submitted to it, laying down his life for the sheep. In other words: Jesus was the one person who ever lived who was, from the womb, seeing. And in giving his life as a ransom for many he allowed himself to be made blind so that you and I, blind beggars asking for glory, can see. For free.