હાજીભાઈએ હદ કીધી, મુઈ ઘોડીને બરછીએ દીધી.

hājībhāīē hada kīdhī, muī ghōḍīnē barachīē dīdhī.

Literally: Hajibhai crossed all limits, he struck the dead mare with a spear.
What it means: Attacking or abusing someone who is already defeated and defenseless.

Also said as

ગુજરાતી કહેવતસંગ્રહ (Gujarati Kahevat Sangrah) (1921) · 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.