Sayyiduna Ibn Umar (may Allah be pleased with them both) said: The Prophet (peace and blessings be upon him) turned towards us and said: "No people withhold the zakah of their wealth except that rain from the sky is withheld from them, and were it not for the animals, they would not be given rain at all."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13562