Verse 7 presents a challenging proposition regarding prophecy and God's active involvement in the governance of His creation. Jesus can say this only if God will use His powers purposely to increase the number and intensity of these plagues in a variety of places, even where they are not normally experienced. No study has ever shown that these things increase or decrease according to uniform law, especially in widely divergent places. Jesus intimates that they will increase unusually and rather suddenly.
Psalm 147:15-20 shows God actively exercises His sovereignty daily in good times and bad. His involvement is not limited to the big disasters we call "acts of God," though they are certainly included:
He sends out His command to the earth; His word runs very swiftly. He gives snow like wool; He scatters the frost like ashes; He casts out His hail like morsels; who can stand before His cold? He sends out His word and melts them; He causes His wind to blow, and the waters flow. He declares His word to Jacob, His statutes and His judgments to Israel. He has not dealt thus with any nation; and as for His judgments, they have not known them. Praise the LORD.
Regarding "acts of God," Amos 4:6-9, 13 provides arresting insight into why God uses them to intervene in the affairs of men:
"Also I gave you cleanness of teeth in all your cities. And lack of bread in all your places; 'Yet you have not returned to Me,'" says the LORD. "I also withheld rain from you, when there were still three months to the harvest. I made it rain on one city, I withheld rain from another city. One part was rained upon, and where it did not rain the part withered. So two or three cities wandered to another city to drink water, but they were not satisfied; yet you have not returned to Me," says the LORD. "I blasted you with blight and mildew. When your gardens increased, your vineyards, your fig trees, and your olive trees, the locust devoured them; yet you have not returned to Me," says the LORD . . . . For behold, He who forms mountains, and creates the wind, who declares to man what his thought is, and makes the morning darkness, who treads the high places of the earth—the LORD God of hosts is His name.
Is God involved? Certainly! He does these things to grab people's attention and turn them back to Him!