1 Samuel 12:16

That mighty deed Samuel is said to have accomplished through prayer is something that everyone who genuinely relies on God can accomplish spiritually even now, since he has become worthy of being heard.… For every saint and genuine disciple of Jesus is told by the Lord, "Lift up your eyes, and see how the fields are already white for harvest. He who reaps receives wages and gathers fruit for eternal life." In this time of harvest the Lord does "a great thing" before the eyes of those who hear the prophets. For when the one adorned with the Holy Spirit calls to the Lord, God gives from heaven thunder and rain that waters the soul, so that he who once was in evil may stand in great awe of the Lord and his minister of goodness, manifested as venerable and august by the requests that are heard. And Elijah, who shut up heaven for the wicked for three and a half years, later opened it. This, too, is always accomplished for everyone who through prayer receives the rain of the soul, since the heavens were previously deprived of it because of his sin.

Therefore it is well added: "But now also stand and see this great thing which the Lord will do before your eyes. Is it not the wheat harvest today? I will call upon the Lord, and He will send thunder and rain; and you shall know and see that you have done a great evil for yourselves in the sight of the Lord, in asking for a king over you." 9. Because the petition of the king is reproved so attentively and so many times, this suggests to the elect that those who advance carnal men to the height of the holy Church are held by a most grave obligation of sin. For other sins obtain the merit of a single punishment, but he who appoints a carnal leader incurs as many merits of punishment as that man provides examples of depravity to the faithful subjects. But the heavy weight of crime cannot be set down except by the severity of great compunction. Yet the grace of compunction is not poured into the mind unless the magnitude of the sin is first shown to it. Therefore the prophet of the Lord, in order to provoke the sinning people to the fruit of fitting penance, suggests to them the great sin of transgression through a wondrous disturbance of the air. Now in that region, rains and thunders do not occur during the wheat harvest.

As a matter of fact, the works Moses did, Samuel did too. Moses resisted God and prevented him from destroying his people when God said to him, "Let me alone, that I may strike this people." Just see the power of Moses! What does God say to him? Let me alone; you are compelling me, your prayers, as it were, restrain me; your prayers hold back my hand. I shoot an arrow; I hurl a javelin; and your prayers are the shield of the people. Let me alone that I might strike down this people. Along with this, consider the compassionate kindness of God. When he says, "Let me alone," he shows that if Moses will continue to importune him, he will not strike. If you, too, will not let me alone, I shall not strike; let me alone, and I shall strike. In other words, what does he say? Do not cease your persistent entreaty, and I shall not strike.Let us see if Samuel persistently importuned God in this way. We read in the book of Kings [Samuel] that he prevented God from venting his wrath against the people, and although it was harvest time, the Lord sent rain, thunder and lightning. What does Scripture say in Samuel? "And there came hailstones and struck down the Philistines." See how wise the fire, how wise the hail! Where Samuel is, the thunderbolts do not dare to strike, for they see the prophet of God, they see the Levite. Samuel's hands were threatening the thunderbolts. He was praying, and the lightning strokes were held back. Why have I said all this? Because Moses and Aaron and Samuel with different titles performed the same mighty deeds. Let us bless the Lord to whom be glory forever and ever.