John Calvin Commentary Isaiah 19:20

"And it shall be for a sign and for a witness unto Jehovah of hosts in the land of Egypt; for they shall cry unto Jehovah because of oppressors, and he will send them a saviour, and a defender, and he will deliver them." — Isaiah 19:20 (ASV)

And he will send them a Savior. We cannot serve God unless He first bestows His grace upon us, for no one will dedicate himself to God until he is drawn by His goodness and embraces Him with all his heart. He must therefore call us to Him before we call upon Him; we can have no access until He first invites us.

Previously, he showed that they must be subdued by various afflictions so that they may submit to God, and now he repeats the same thing; for people never deny themselves and forsake idle follies any further than the scourge compels them to yield obedience. But he also adds another kind of invitation: that having experienced the kindness of God, they will freely approach Him.

They will cry unto the Lord. The cry of which he speaks proceeds from faith, for they would never resort to this refuge until they had been allured and delighted by the goodness of God. When the Lord promises that He will send a Savior, by whose hand the Egyptians will be delivered, this can mean no other than Christ, for Egypt was not delivered from its distresses before the doctrine of Christ reached it.

We read of various changes that country suffered for four hundred years, foreign and civil wars by which it was devastated and almost destroyed. But when we would be ready to think that it is utterly ruined, behold! It is converted to the Lord and is rescued from the hand of enemies and tyrants. Thus Christ delivered that country when it had begun to know Him.

Similarly, we must be brought to the knowledge and worship of God, so that where we have suffered various afflictions, we may learn that salvation is found in Him alone. If only the world would now learn this lesson, having suffered so many calamities that it appears to be on the brink of ruin! For what can be the outcome except that it will either perish or by repentance acknowledge that it has been justly punished for such great wickedness?

That he may deliver them. When he adds these words, we should draw from them a profitable doctrine: that God assists us through Christ, by whose agency He gave deliverance to His own people from the beginning. He has always been the Mediator, by whose intercession all blessings were obtained from God the Father; and now that He has been revealed, let us learn that nothing can be obtained from God except through Him.