The tide must be taken when it comes
Possible interpretation: We should use all opportunities when they come, before it's too late.Note: (the) tide (noun) = the rising and falling of the sea caused by the attraction of the moon and sun | Compare: "There is a tide in the affairs of men, Which taken at the flood, leads on to fortune..." (from "Julius Caesar" by William Shakespeare 1564-1616)
Origin: Ships (especially in the old days) often need a high tide to leave or enter port. Man cannot control the tide, so when it comes ships have to use the opportunity it gives them without delay.
"The tide must be taken when it comes" is a saying suggesting that we