Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said: "The one who withholds and delays (paying) charity (zakah) has been declared accursed on the tongue of Muhammad (peace and blessings be upon him) on the Day of Resurrection."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7226