Moses fought cynicism and prayed for pharaoh--again.
Observe,
(1.) The place Moses chose for his intercession.
He went out of the city(Exodus 9:33), not only for privacy in his communion with God, but to show that he durst venture abroad into the field, notwithstanding the hail and lightning which kept Pharaoh and his servants withindoors, knowing that every hail-stone had its direction from his God, who meant him no hurt. Note, Peace with God makes men thunderproof, for thunder is the voice of their Father.
(2.) The gesture:
He spread abroad his hands unto the Lord--an outward expression of earnest desire and humble expectation. Those that come to God for mercy must stand ready to receive it.
(3.) The end Moses aimed at in interceding for him:
That thou mayest know, and be convinced, that the earth is the Lord's (Exodus 9:29), that is, that God has a sovereign dominion over all the creatures, that they all are ruled by him, and therefore that thou oughtest to be so. See what various methods God uses to bring men to their proper senses. Judgments are sent, judgments removed, and all for the same end, to make men know that he Lord reigns.
Matthew Henry