labor the point
US /ˈleɪbər ðə pɔɪnt/
UK /ˈleɪbər ðə pɔɪnt/

1.
to explain something in too much detail or to repeat it unnecessarily, making it boring or tedious
:
•
I don't want to labor the point, but it's crucial that we finish this by Friday.
•
He tends to labor the point when he's trying to convince someone.