«وَلَا أُفْرِغُ ثَنَائِي عَلَى مَنْ يُفْرِغُ إِنَائِي»
I will not pour praise upon one who empties my vessel.
The same root governs two acts: the speaker does not pour out praise, while the other person pours out the contents of a vessel. The parallel verbs give the rebuke its edge. Translating both as merely “give” would flatten the construction.
“Pour praise” is a marked English phrase, but that strangeness is useful: the Arabic also turns an abstract evaluation into something liquid. “I do not praise him” conveys the basic stance but discards the image and the pointed reciprocity.
Translation exercise
Keep the verb “pour” in both clauses and distinguish the two objects.