De Sacrificiis Abelis Et Caini
Philo Judaeus
The works of Philo Judaeus, the contemporary of Josephus, volume 1. Yonge, C. D., translator. London: Henry G. Bohn, 1854.
But when Moses says that God swears, we must consider whether he really asserts this as a thing appropriate for him to do; since to very many people it appears inconsistent with the character of God; for the meaning implied in an oath is, that it is the testimony of God in a matter which is doubtful. But to God there is nothing uncertain and nothing in doubt;