One of the most beautiful flowers that God has created is the rose. Such as is our lives; the beautiful flower of our life is like the rose: having thorns. Paul, David and Peter all had thorns in their lives - something with sharpness and pain. The lesson is that there is no rose without thorns.
The thorns in our lives are there to help us - to teach us, humble us and keep us dependent on Christ. As we see from the examples of the patriarchs in Scripture that we can harness the thorns to learn lessons and grow spiritually, turning them into a positive aspect of our life.