Charles H. Spurgeon on Psalms 66:12

We went through fire and through water. There was a great variety of such perils; and not only of several, but of contrary sorts: We went through fire and through water, either of which singly and alone denotes an extremity of evils. Thus, through water (Ps 69:1-2): "Save me, O God; for the waters are come in unto my soul. I sink in deep mire, where there is no standing: I am come into deep waters, where the floods overflow me." Or, through fire (Eze 15:7): "And I will set my face against them; they shall go out from one fire, and another fire shall devour them; and ye shall know that I am the Lord, when I set my face against them." But when through both successively, one after the other, this denotes an accumulation of miseries, or trials, indeed: as we read Isa 43:2, with God's promise to his people in such conditions: "When thou passest through the waters I will be with thee; and through the rivers, they shall not overflow thee: when thou walkest through the fire, thou shalt not be burned; neither shall the flame kindle upon thee." Which promise is here, you see, acknowledged by the psalmist to have been performed: God was with the three children when they walked through the fire, in the very letter of Isaiah's speech; and with the children of Israel when they went through the water of the Red Sea. Thomas Goodwin.