«وَكِلْتُ لِلْخِلِّ كَمَا كَالَ لِي / عَلَى وَفَاءِ الْكَيْلِ أَوْ بَخْسِهِ»
I measured out to my friend as he measured to me, whether the measure was full or diminished.
Al-khill means an intimate friend. Kāla/kiltu refers to measuring goods. The poet imports an ordinary market transaction into the language of friendship.
The idea is a response proportionate to what one receives. Yet the next verse qualifies this image: the speaker does not wish to shortchange another person. The poem must not be reduced to a simple demand for revenge.