John Gills Exposition of the Bible Commentary - Exodus 7:22
And the magicians of Egypt did so with their enchantments ,.... Who were either in company with Pharaoh and his nobles, or were immediately sent for to try their art, and confront Moses and Aaron with it; and who very probably got a little water in a vessel, and by some juggling trick imposing upon, and deceiving the sight of Pharaoh and his servants, made it look like blood; and the devil might help them to a sufficient quantity of blood, and discolour the water with it, and make it appear... read more
Matthew Henry's Complete Commentary - Exodus 7:14-25
Here is the first of the ten plagues, the turning of the water into blood, which was, 1. A dreadful plague, and very grievous. The very sight of such vast rolling streams of blood, pure blood no doubt, florid and high-colored, could not but strike a horror upon people: much more afflictive were the consequences of it. Nothing more common than water: so wisely has Providence ordered it, and so kindly, that that which is so needful and serviceable to the comfort of human life should be cheap,... read more