The Underground Railroad by Colson Whitehead:
Jasper wouldn’t stop singing. Ridgeway shouted from the head of their little caravan for him to shut his mouth, and sometimes they halted so Boseman could climb into the wagon and clout the runaway on the head. Jasper sucked the scars on his fingers for a short interval, then resumed his crooning. Quietly at first so that only Cora could hear. But soon he’d be singing again, to his lost family, to his god, to everyone they passed on the trail. He’d have to be disciplined again.
Cora recognized some of the hymns. She suspected he made up many of them; the rhymes were crooked. She wouldn’t have minded it so much if Jasper had a better voice, but Jesus had not blessed him in that department. Or with looks—he had a lopsided frog face and oddly thin arms for a field hand—or with luck. Luck least of all.