I say, and with God's success: If he does not pay the zakat until the end of his life, the obligation becomes tight on him if there remains enough time for him to perform it, and he is led to believe that if he does not pay it, he will die and miss it. At that point, the obligation becomes tight on him, to the extent that if he does not pay it until he dies, he will be sinful, unless he bequeaths its payment from the estate. It is then obligatory for the heirs to pay it from the estate as long as it does not exceed one-third of the estate. If the amount of zakat exceeds one-third of the estate, he needs the heirs' consent to pay the excess over one-third. As mentioned in Bada'i' al-Sana'i (4:2), and God knows best.