Numbers 14:33

Your children shall wander, &c.— Shall associate together like a flock, רעים raim; which possibly alludes to the manner of the Arabian shepherds, who removed their tents from place to place that they might find pasture for their flocks. The forty years are to be reckoned from their first coming out of Egypt into the wilderness. Respecting the word whoredoms, we have before observed, that idolatry and defection from God, to whom they were espoused by covenant, are constantly represented in Scripture under this idea; see Exodus 34:16 and Amos 5:25.