It is narrated from Sayyiduna Qurrah bin Iyas (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever is approached by death and makes his will according to the rulings of the Book of Allah, that becomes an expiation for whatever shortfall remained in his zakah during his lifetime."
Hadith Referenceالمعجم الكبير للطبراني / باب القاف / 16119