"a prisoner of promise"

Normally when we think of a prisoner we naturally only think in negative terms. A prisoner is one who is being held against their will and dying to break free. A person who is held captive but someone or something greater than themselves...

What would life look like if that stronger, captivating force were the Promises of God?

Oh, to live the life of a prisoner of promise.

"..and now these three remain: faith, hope, and love.." (I Corinthians 13:13)

We definitely need God's faith for the present ("Now faith is.." Hebrews 11:1) but it doesn't help our past much. We need God's love to cover our past and all of it's failures.
And in regards to our future, it is true, biblical hope that draws us towards God's purpose and destiny.

Abraham was the father of our faith. The Bible says that when he found himself in a situation that for every good reason looked hopeless....he had hope....against all hope, he hoped.
(Romans 4:18)

The question reigning in the heart and mind of such a person is no longer "if" but rather "when".

Abraham's reliance on God was so strong that he was literally held hostage to hope and a prisoner of promise.