backslider

The prodigal was a backslider: when furthest from home he could yet think and speak of the privileges of his father's house.

He was a backslider, and had stopped in passing, being attracted by a hymn I was singing—one his mother used to sing.

Retire then, thou poor backslider, from the haunts of evil—and yet hope for mercy.

If a sinner, newly awakened, be in danger of this species of despondency, a backslider is still more so.

A man isn't a backslider because he's carnally weak, and a man isn't a saint because he's moral and well-behaved.