I copied the following from the second volume, and I did not hear it directly:
24 – Through his chain of transmission he relates: Ibn al-Zubayr wrote to Muʿāwiyah, saying, “You already know that I am the master of the House and that I am the caliph after ʿUthmān. I shall do such-and-such and such-and-such.” Muʿāwiyah then summoned Yazīd and asked, “What is your view?” Yazīd replied, “By Allah, even if you and he were equals, you should not tolerate this from him.” Muʿāwiyah said, “What, then, do you suggest?” Yazīd answered, “I think you should send cavalry against him.” Muʿāwiyah said, “Woe to you! I cannot get to Ibn al-Zubayr without first having to kill men of Quraysh on his behalf. How many do you think I should dispatch?” Yazīd said, “Forty thousand horsemen.” Muʿāwiyah asked, “And how many feedbags will suffice them?” He replied, “Forty thousand feedbags—one dirham for each feedbag—so that comes to forty thousand dirhams.” Muʿāwiyah said, “Boy, write to Ibn al-Zubayr: ‘The Commander of the Believers has sent you thirty thousand dirhams to assist you in your affair.’ ”
Ibn al-Zubayr wrote back, “A bond of kinship has reached the Commander of the Believers.” Muʿāwiyah then said to Yazīd, “We have saved ten thousand dirhams on the feedbags with Ibn al-Zubayr.”