'Mightily' in the Bible

And Amaziah separateth them -- for the troop that hath come in unto him from Ephraim to go to their own place, and their anger doth burn mightily against Judah, and they turn back to their place in the heat of anger.

The Israelis who were present in Jerusalem observed the Festival of Unleavened Bread for seven days with immense gladness, and the descendants of Levi and priests praised the LORD throughout each day, singing mightily to the LORD.