ËÈÒÜ ÂÎÄÓ ÍÀ ÷üþ-ëèáî ÌÅËÜÍÈÖÓ
[lit' vodu ïà m'el'nitsu]
To pour water on someone's mill-wheel.
Indirectly to help someone (usually an opponent) by one's actions.
Cf. To play into someone's hands; to bring grist to someone's mill.