Jesus had just spoken to the crowd, and the disciples asked why he spoke to them in parables. It was because they were not ready to see and hear what Jesus had to say. They had not yet been made worthy of understanding.
When I first read this section I was confused because I thought Jesus was saying the rich would get more and the poor would get less, which contradicts his other teachings. Maybe it was because I wasn't ready to understand. But I get now that those who have the knowledge of Jesus will continue to get more and be rich, and those who do not have the knowledge will have everything taken from them. We must be ready to see, hear and listen, and understand the knowledge of the kingdom of God.
Lord, open my eyes, my heart, and my mind so that I am ready to know you. Amen.