Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[235] When Herod heard this confession, he was all over anger and fear, some parts seeming to him reproachful, and some made him suspicious of dangers that attended him, insomuch that on both accounts he was provoked, and bitterly afraid lest some more heavy plot was laid against him than he should be then able to escape from; whereupon he did not now make an open search, but sent about spies to watch such as he suspected, for he was now overrun with suspicion and hatred against all about him; and indulging abundance of those suspicions, in order to his preservation, he continued to suspect those that were guiltless; nor did he set any bounds to himself, but supposing that those who staid with him had the most power to hurt him, they were to him very frightful; and for those that did not use to come to him, it seemed enough to name them [to make them suspected], and he thought himself safer when they were destroyed. And at last his domestics were come to that pass, that being no way secure of escaping themselves, they fell to accusing one another, and imagining that he who first accused another was most likely to save himself; yet when any had overthrown others, they were hated; and they were thought to suffer justly who unjustly accused others, and they only thereby prevented their own accusation; nay, they now executed their own private enmities by this means, and when they were caught, they were punished in the same way. Thus these men contrived to make use of this opportunity as an instrument and a snare against their enemies; yet when they tried it, were themselves caught also in the same snare which they laid for others: and the king soon repented of what he had done, because he had no clear evidence of the guilt of those whom he had slain; and yet what was still more severe in him, he did not make use of his repentance, in order to leave off doing the like again, but in order to inflict the same punishment upon their accusers.