The only thing that will ever lift you out of your sin and complacency, put you on the pilgrim trail, and keep you there throughout life is a profound awareness of the mercy and grace of God.
Consider the example of John Newton, the hymn writer. When Newton was a young boy he ran away to sea and eventually went to Africa to participate in the slave trade. His reason for going, as he wrote in his autobiography years later, was that he might “sin his fill.” Sin he did! But the path of sin is downhill, and Newton’s path descended so far that he was eventually reduced to the position of a slave in his master’s African compound. This man dealt in slaves, and when he went off on slaving expeditions Newton fell into the hands of the slave trader’s African wife, who hated Europeans and vented her venom on Newton. Newton was forced to eat his food off the dusty floor like a dog, and at one point he was actually placed in chains. Sick and emaciated, he nearly died.
Newton escaped from this form of his slavery eventually, but he was still chained to sin and again went to sea transporting slaves from Africa to the New World. It was on his return from one of these slave voyages that Newton was wondrously converted.
The ship was overtaken by a fierce storm in the North Atlantic and was nearly sinking. The rigging was destroyed, water was pouring in. Newton was sent down into the hold to pump water. He pumped for days, certain that the ship would sink and he would be drowned. As Newton pumped water in the hold of that ship, God caused him to remember Bible verses he had learned from his mother as a child, half a lifetime earlier, and these verses led to his repentance, faith, and conversion. Right there in the ship! While the storm was raging!
The ship survived the storm. The sailors were saved. Sometime later, after Newton had left the slave trade, this former slave of slaves studied for the Christian ministry and eventually became a popular preacher in England. He even preached before the queen.
What was Newton’s motivation? It was a profound awareness of the grace and mercy of God toward him. It was this John Newton who wrote,
Amazing grace!—how sweet the sound--
That saved a wretch like me!
I once was lost, but now am found,
Was blind, but now I see.
Newton never forgot God’s mercy to him. Once, a friend was complaining about someone who was resistant to the gospel and living a life of great sin. “Sometimes I almost despair of that man,” the friend remarked.
“I never did despair of any man since God saved me,” said Newton.
In his most advanced years Newton’s mind began to fail and he had to stop preaching. When friends came to visit him he frequently remarked, “I am an old man. My mind is almost gone. But I can remember two things: I am a great sinner, and Jesus is a great Savior.” Certainly the mercy of God moved Newton to offer his body as a living sacrifice to God and to seek to please him.
Above is taken from Boice, James Montgomery. Psalms 107–150: An Expositional Commentary. Grand Rapids, MI: Baker Books, 2005.