"He who sits in the heavens shall laugh." Rabbi Yitzhak said: All of God's dealings are holy. His speech is in holiness, as it is said, "God has spoken in His holiness." His measurements are in holiness, as it is said, "Holy, holy, holy."
His movements are in holiness, as it is said, "In holiness, the steps of the king approach me." His vows are in holiness, as it is said, "Who is like You among the mighty, O Lord, who is like You, majestic in holiness?" Another interpretation: "He who sits in the heavens shall laugh." God said, "These [people] mock one another."
Rabbi Aha in the name of Rabbi Samuel bar Nahmani said: These are the four [verses] of laughter: (a) "He who sits in the heavens shall laugh," (b) "But You, O Lord, shall laugh at them," (c) "The Lord shall laugh at him," (d) "I, too, will laugh at your calamity."