'Rigorous' in the Bible

They made their lives bitter by hard service with mortar and bricks and by all kinds of service in the fields. Every kind of service the Israelites were required to give was rigorous.

he answered and said to Arioch the king's captain, Why is the decree so rigorous from the king? Then Arioch made the thing known to Daniel.

Forasmuch as the king's commandment was rigorous, and the furnace exceeding hot, the flame of the fire slew those men that had taken up Shadrach, Meshach, and Abed-nego.