belabor the point - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Repeat an argument or other issue over and over, harp on something, as in We've discussed her decision—let's not belabor the point. This term dates from the mid-1900s and derives from belabor in the sense of “assail with words,” a usage dating from the late 1500s.