EXOD17 The midwives risked their lives by defying Pharaoh's order to kill the male babies. They saved thousands of Jewish children from death, not merely by passively allowing them to live, but by actively supplying them with food (See Rashi on this verse). How great it was their heroism! "Whoever saves one life it is if he has saved an entire world" Sanhedrin 37a. All the more so the midwives to save so many lives. But when the Torah praises them, what words does it use? "But the midwives feared God, and they did not do as the king of Egypt had spoken to them." The Torah emphasizes that their main virtue was their awareness of God. All virtues depend on this attribute, for it is the main achievement in life. Moreover, the only means by which two women could acquire such bravery to defy the orders of the king of Egypt is by their having fear of a greater King--Almighty God. Ohr Yohail, vol. 2. Shmos.