flex your muscles idiom
(US flex your muscle)（通过军事、政治或经济实力的展示向对手）显示实力，显示力量
to try to worry an opponent or enemy by publicly showing military, political, or financial power
The parade is the first sign of the new regime flexing its military muscles. 阅兵式是新政权显示其军事实力的第一个信号。
See also: muscle-flexing