flex (your) muscles

if a person or an organization flexes their muscles, they take some action to let people know how powerful they are.

The latest bomb scare was just the terrorists flexing their muscles - showing us they haven't gone away.

• with might and main
• with mixed feelings
• with money to burn
• with nose in the air
• with one eye on
• with one eye on someone
• with one eye on something
• with one hand tied behind back
• with one hand tied behind your back
• with open arms
• without a backward glance
• without a care in the world
• without a murmur
• without a second thought
• without a shadow of a doubt
• without fail
• without further ado
• without missing a beat
• without more ado
• without question
• without rhyme or reason
• without so much as a by-your-leave
• with own fair hands
• with regard to
• with regard to something