Psalms 105:29

As the believer commonly thrives best in his soul when under the cross; so the church also flourishes most in true holiness, and increases in number, while under persecution. Yet instruments shall be raised up for their deliverance, and plagues may be expected by persecutors. And see the special care God took of his people in the wilderness. All the benefits bestowed on Israel as a nation, were shadows of spiritual blessings with which we are blessed in Christ Jesus. Having redeemed us with his blood, restored our souls to holiness, and set us at liberty from Satan's bondage, he guides and guards us all the way. He satisfies our souls with the bread of heaven, and the water of life from the Rock of salvation, and will bring us safely to heaven. He redeems his servants from all iniquity, and purifies them unto himself, to be a peculiar people, zealous of good works.

He turned their waters into blood, and slew their fish. So that the plague was not a mere colouring of the water with red earth, as some suppose, but the river was offensive and fatal to the fish. The beloved Nile and other streams were all equally tainted and ensanguined. Their commonest mercy became their greatest curse. Water is one of the greatest blessings, and the more plentiful it is the better, but blood is a hideous sight to look upon, and to see rivers and pools of it is frightful indeed. Fish in Egypt furnished a large part of the food supply, and it was no small affliction to see them floating dead and white upon a stream of crimson. The hand of the Lord thus smote them where all classes of the people would become aware of it and suffer from it.