Father Girardey remarks: “One of the most beautiful examples of this power of prayer over God Himself is given us by Moses.” It happened in this way:
“Whilst Moses was spending on Mount Sinai forty days in fasting and prayer, communing with God and receiving from Him the tables of the Ten Commandments and the necessary directions to draw up the Old Law for the Israelites, these latter fell into idolatry, adoring the golden calf. . . . God said to Moses: ‘Go, get thee down; thy people whom thou hast brought out of the land of Egypt, hath sinned. They have quickly strayed from the way, which thou didst show them; and they made themselves a molten calf, and have adored it and sacrificed victims to it. . . . Let Me alone, that My wrath may be kindled against them, and that I may destroy them.'”
“Why does God ask Moses to let Him alone and not to prevent Him from destroying the Israelites? What could Moses do against God’s will and His almighty power? Of himself he could do nothing! But Moses could pray for the Israelites and implore God to forgive them. The very words of God were a sufficient hint to Moses about the power he could wield in restraining God’s justice and obtaining mercy for the idolatrous people. Moses took the hint and ‘besought the Lord, saying: Why, O Lord, is thy indignation enkindled against Thy people? . . . Let Thy anger cease, and be appeased upon the wickedness of Thy people. . . . And the Lord was appeased from doing the evil which He had spoken against His people’ (Exod 32:1-14).”
“This clearly shows us the almighty power of prayer, that its power is so great as to be able to stay the divine justice irritated against the sinner. . . . Wherefore St. Augustine says: ‘In order to escape the punishments of God’s justice, we sinners have only to pray to Him for mercy.’ . . . Our confidence in prayer should, therefore, know no bounds.”
Quotations from Ferreol Girardey, Prayer: Its Necessity, Its Power, Its Conditions (St. Louis: B. Herder, 1916).