Well God did use Rahab the harlot to bring King David into existence, and the Man Christ Jesus afterward...............(I'm referring to Christ's physical birth here on Earth).
She wasn't exactly a shining example for righteous living, but she is mentioned in at least one of the genealogies of Christ. And has an honorable mention in Hebrews 11.
"For I have not come to call the righteous, but sinners, to repentance." - Luke 5:32