(3) The conversion of the rivers and fountains of waters into blood: “ And the third angel poured out his vial upon the rivers and fountains of waters; and they became blood” --16:4. The pollution of the fountains and streams of water resulted in epidemics of deadly disease. The sickening figure of the total contamination of the streams of water by the effluence of blood was symbolic of retribution for the blood of the martyrs. In chapter 6:10 the souls under the altar of martyrdom cried: How long, 0 Lord, holy and true, dost thou not judge and avenge our blood on them that dwell on the earth? This plague symbol was the answer to the martyr-cry. It was the squaring of the account in this symbolic retribution of blood, the avenging of the martyrs. And verse six so declares: For they have shed the blood of the saints and prophets, and thou hast given them blood to drink; for they are worthy. The statement “ for they are worthy” means that they deserved the recompense of blood for the blood they had shed. A similar pronouncement of judgment upon apostate Jerusalem was made by Jesus in Matthew 23:37 : “ 0 Jerusalem, Jerusalem, thou that killest the prophets, and stonest them which are sent unto thee, how often would I have gathered thy children together, even as a hen gathereth her chickens under her wings, and ye would not!” The plague meant that they were figuratively made to drink the blood which they had made to flow from the mass murder of the saints.