Though ye once: this may be joined either with the verb following, knew, according to our translation, and the sense is, though ye knew this certainly, as the word once is taken, Psa_89:35, or perfectly and thoroughly, or once for all; or rather, with what goes before, and the words may be read, I will yet once (viz. while I am in this tabernacle) put you in remembrance of this, though you know it; as 2Pe_1:12.
Having saved the people; the people of Israel.
Afterward destroyed them; viz. in the wilderness, by plague, fiery serpents, &c.
That believed not; he sets forth the Israelites’ unbelief, as the original of all their disobedience and rebellions, and the great cause of their destruction. See Heb_3:17-19 4:2.