Amazing grace

I think Amazing Grace is a wonderful song.
The reason is it has been loved and inherited by many people until today.
But There was the part which I was not able to hear well in the video. So, I examined it later.
John Newton who wrote the words has done a slave trade. However, when he encountered a storm in the ship, he prayed to God desperately. And he was helped. He got reverted afterwards and became a clergyman. This music was born to convey an amazing change of his mind.
　Not only the melody is nice, but the words and background are great.