To harp on a point far longer than necessary.
To most commonly means to explain or discuss something in excessive, often annoying, detail. Quick Definitions belabor
"The speaker belabored the issue until the audience lost interest". Key Comparisons Labor vs. Belabor - DAILY WRITING TIPS To harp on a point far longer than necessary
The word is most often used in the idiom or "belabor the obvious" . belabor