鑒往知來

to observe the past to foresee the future (idiom, taken loosely from Book of Songs); studying ancient wisdom gives insight into what is to come

variant of 鑑|鉴[jian4]

to go (in a direction) / to / towards / (of a train) bound for / past / previous

old variant of 往[wang3]

to know / to be aware

to come / to arrive / to come round / ever since / next