Adam Clarke on Psalms 66:12

Thou hast caused men to ride over our heads - Thou hast permitted us to fall under the dominion of our enemies; who have treated us as broken infantry are when the cavalry dashes among their disordered ranks, treading all under the horses' feet.

We went through fire and through water - Through afflictions of the most torturing and overwhelming nature. To represent such, the metaphors of fire and water are often used in Scripture. The old Psalter considers these trials as a proof of the uprightness of those who were tried - We passid thrugh fire and watir: that is, thurgh wa and wele, as a man that leves noght his waye for hete na for kald, for dry na for wette; and thou out lede us fra tribulacyon intill koling (cooling) that is, in till endles riste, that we hope to hafe after this travell.

Wealthy place - Well watered place, to wit, the land of Judea.