Exodus 15:13

13.Thou in thy mercy hast led them forth. (164) The verb in Hebrew is indeed in the past tense; but, since it is plain from the context that their hope for what was to come was founded on God’s former mercies, I have preferred making the meaning clearer by translating it in the future. (165) Moses, therefore, exhorts the people to proceed to their promised land boldly and joyfully; because God will not forsake His work in the midst of it. And on this account he expressly mentions their redemption; as though he had said, that the people were not in vain delivered from impending death, but that God, as He had begun, would be their constant guide. David uses the same argument, (Psalms 31:5,)

“Into thine hand I commit my spirit; thou hast redeemed me,
O Lord God of truth.”

For, as the beginning of their redemption has proceeded from God’s mere mercy, so he says that for this same reason He will lead them even to their promised inheritance. But, since the many obstacles might impress them with alarm, he at the same time sets before them the “strength” of God; for the whole praise is given to God, who had both been freely gracious to His people, and, asking assistance from no other source, but contented with His own power, had supplied what would have been otherwise incredible.