હાજભાઈએ હદ કીધી, મુઈ ઘોડીને બરછીએ દીધી.

hājabhāīē hada kīdhī, muī ghōḍīnē barachīē dīdhī.

Literally: Hajbhai crossed all limits; he stabbed the dead mare with a spear.
What it means: Said of someone who performs a useless, redundant, or excessively aggressive action on something that is already ruined or dead.

Also said as

ગુજરાતી કહેવતસંગ્રહ (Gujarati Kahevat Sangrah) (1923) · read from the scan by machine — the Gujarati itself is unchecked · English is machine-made and nobody has checked it yet

Heard it differently, or know we've got the sense wrong? Tell us — that is exactly the kind of correction this needs.