rule with a rod of iron

To rule, govern, or control a group or population with complete power over all aspects of life, work, etc. He rules with a rod of iron, and moves swiftly to gain control over any entity that is not already in his grasp. She has ruled this company with a rod of iron for three decades, and it's going to be difficult for her to let go of control.

rule someone or something with a rod of iron

control or govern someone or something very strictly or harshly.

This expression comes from Psalm 2:9: ‘Thou shalt break them with a rod of iron; thou shalt dash them in pieces like a potter's vessel’.

See also: iron, of, rod, rule, someone, something

rule (somebody/something) with a rod of ˈiron/with an iron ˈhand

(informal) control somebody/something in a very strong or strict way: They ruled the country with an iron hand and anybody who protested was arrested.