[jiè gǔ yù jīn]   

借    古    喻    今    借：假借；喻：比喻。假借古人古事比喻现实中的今人今事。

借古喻今指假借古人古事比喻现实中的今人今事。

Narrate anecdotes of the past in alluding to the present

借水行舟    借酒浇愁    借交报仇    借公行私    借身报仇