It seems to me the “Reckon ye yourselves to be dead to sin” cannot be found in the Red Sea passage but rather in the passage of the Jordan. There they were commanded to “sanctify themselves” (Joshua 3:5). There, at Gilgal, they were called to a second circumcision and there we are told that the Lord “rolled away the reproach of Egypt” from off them. Does not all this signify far more than the scene of the Red Sea tells us? Have we not in Romans 6:11 Gilgal reckoning, in Romans 6:12 Gilgal separation, and in Colossians 3:1 Gilgal dwelling? We can easily see how an Israelite must have felt his separation from Egypt when he was circumcised like this in the land of promise; and we can only know the manifest rolling away of the reproach of Egypt, as we stand by faith in heavenly places, and walk even as Christ walked in newness of life. Then too the manna ceased after they had crossed the river and they ate the old corn of the land.
So when we realize ourselves as a heavenly people, it is Christ who belongs to heaven that we feed upon, a risen Christ seated at the right hand of God, ever living to make intercession for us. Certainly the land of rest was a better place than the wilderness, and it was only the failure of the Israelites, or rather their unbelief, that kept them out of it so long. So that they were practically walking in sin during all those forty years, delivered from Egypt it is true, but very far from being in the place or the position that God had called them to. Both passages were types of the death of Christ, but of that death viewed in two aspects.
And does not this way of viewing them run parallel with the experience of nearly every Christian? First we know redemption from the guilt of sin merely and deliverance from the bondage of Satan; then we wander in a wilderness truly having God with us, as He was with the Israelites and sustained by His bread sent down from heaven, pleasing Him sometimes, grieving him often, needing strict discipline, and growing footsore and tired. Then at last we see that our crucifixion with Christ has a fuller meaning and leads us into higher privileges and we cross the Jordan and enter into the rest of faith, into the life hid with Christ in God, and all our wanderings are over forever.
—To Anna, September 4, 1867

Hannah Whitall Smith and Melvin Easterday Dieter, The Christian’s Secret of a Holy Life: The Unpublished Personal Writings of Hannah Whitall Smith (Oak Harbor: Logos Research Systems, Inc., 1997).